Date:           Wed, 3 Sep 1997 09:01:57 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar


Welcome back everyone.  The MIT combinatorics seminar will resume this
Friday at 4:15pm in 2-338 as usual.  The first speaker will be
Christian Lenart on "The Combinatorics of Steenrod Operations on the
Cohomology of Grassmannians."  See abstract below.

There are some new aspects to our seminar:

1.This year Jim Propp, Maurice Rojas and I (Sara Billey) will be
organizing the seminar.  If you would like to give a talk or know of
anyone who will be in the area that we should invite, please let one
or all of us know: propp(at-sign)math.mit.edu, rojas(at-sign)math.mit.edu,
billey(at-sign)math.mit.edu.

2. We want to invite all of our speakers to contribute an electronic
preprint pertaining to their talk.  These preprints will be on the
combinatorics(at-sign)mit web page.  One can either give us a pointer to a
homepage or we will put the file on our server.  If possible we would
like to have the preprint before the talk is given so people can
familiarize themselves with the work.

3. Our web address has been changed.  This should be pretty permanent.
http://www-math.mit.edu/~combin

(We are in the process of updating it for the fall, it will be ready
momentarily.)

4. As usual, if you know anyone who should be added to the list,
please let us know.  Likewise, anyone who would like to be removed
from the list can write to us directly.  In the next few weeks we will
be installing a email-list maintenance program which will handle
requests for subscriptions and unsubsriptions.  We will keep you
posted on this.

Date: Friday Sept. 5, 1997
Speaker: Christian Lenart
Title: The Combinatorics of Steenrod Operations on the Cohomology
of Grassmannians
Abstract:
The study of the action of the Steenrod algebra on the mod $p$
cohomology of spaces has many applications to the topological structure
of those spaces. In this talk we present some combinatorial formulas for
the action of Steenrod operations on the cohomology of Grassmannians,
both in the Borel and the Schubert picture. We consider integral lifts
of Steenrod operations, which lie in a certain Hopf algebra of
differential operators. The latter has been considered recently  as a
realization of the Landweber-Novikov algebra in complex cobordism
theory; it also has connections with the action of the Virasoro algebra
on the boson Fock space. Our formulas for Steenrod operations are based
on methods which have not been used before in this area, namely  Hammond
operators and the combinatorics of Schur functions. We also discuss
applications of our formulas to the geometry of Grassmannians.


Date:           Fri, 5 Sep 1997 10:26:19 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date: Friday Sept. 5, 1997
Speaker: Christian Lenart
Title: The Combinatorics of Steenrod Operations on the Cohomology
of Grassmannians
Preprint: http://www-math.mit.edu/~combin
Abstract:
The study of the action of the Steenrod algebra on the mod $p$
cohomology of spaces has many applications to the topological structure
of those spaces. In this talk we present some combinatorial formulas for
the action of Steenrod operations on the cohomology of Grassmannians,
both in the Borel and the Schubert picture. We consider integral lifts
of Steenrod operations, which lie in a certain Hopf algebra of
differential operators. The latter has been considered recently  as a
realization of the Landweber-Novikov algebra in complex cobordism
theory; it also has connections with the action of the Virasoro algebra
on the boson Fock space. Our formulas for Steenrod operations are based
on methods which have not been used before in this area, namely  Hammond
operators and the combinatorics of Schur functions. We also discuss
applications of our formulas to the geometry of Grassmannians.

Upcoming events:

Date: Friday Sept. 12, 1997
Speaker: To be announced

Date: Friday Sept. 19, 1997
Title: Brauer diagrams, updown tableaux and conjugacy classes of
nilpotent  matrices

Date: Wednesday, Sept. 24, 1997
Speaker: Alexander Kirillov
Title: Kazhdan-Lusztig polynomials and canonical basis
Preprint: http://www-math.mit.edu/~combin

Preprints and abstracts will be on http://www-math.mit.edu/~combin as
soon as they are available.


Date:           Mon, 8 Sep 1997 15:34:20 -0500
To:             combinatorics(at-sign)math.mit.edu, combinatorics(at-sign)euclid.ucsd.edu
From:           bergeron(at-sign)mathstat.yorku.ca (Nantel Bergeron)
Subject:        FPSAC 98 --- CALL FOR PAPERS


% ********************************************************************** %
%                                                                        %
%           10-th international Conference on                            %
%           Formal Power Series and Algebraic Combinatorics              %
%                                                                        %
%           June 15-19, 1998                                             %
%           Fields Institute, Toronto                                    %
%                                                                        %
%           First announcement -- Call for papers                        %
%                                                                        %
% ********************************************************************** %

TOPICS: Algebraic and bijective combinatorics and their relations with
other parts of mathematics, computer science and physics.

CONFERENCE PROGRAM: Invited lectures, contributed presentations,
poster session, software demonstrations.

OFFICIAL LANGUAGES: English and French.

CALL FOR PAPERS AND POSTERS: Authors are invited to submit extended
abstracts of at most twelve pages before November 21, 1997.
Preferred way of submission is by sending ONE postscript file by
email to

bergeron(at-sign)mathstat.yorku.ca.

If an author is not able to send a postscript version of her/his extended
abstract, four copies of the extended abstract should be mailed to

Nantel Bergeron, Program committee of FPSAC '98
Department of Mathematics and Statistics 61
York University
4700 Keele St.
North York, Ontario, Canada, M3J 1P3.

The submitted papers should begin with a summary written in the two
official languages of the conference (translations will be provided
if necessary). Authors should indicate the mode of presentation
which they consider appropriate for their paper : lecture or poster
session. The notifications of acceptance or rejection are scheduled
for the beginning of March 1998.

The authors whose papers will have been accepted for a lecture or a
poster presentation will have the possibility to submit a complete
version of their work to a special issue of the journal Discrete
Mathematics," devoted to the conference FPSAC '98. The deadline for
submission to the special issue is September 1, 1998.

SOFTWARE DEMONSTRATIONS: Demonstrations of software relevant to the
topics of the conference are encouraged. People interested in giving
a software demonstration should submit a paper as described above,
including the hardware requirements, before January 15, 1997,
by email to

sottile(at-sign)math.toronto.edu.

PROGRAM COMMITTEE:
I. Goulden, Chairman (U. of Waterloo), N. Bergeron (York U.),
S. Billey (USA), F. Brenti (Italy), R. Cori (France), S. Dulucq (France)
K. Eriksson (Sweeden), O. Foda (Australia), S. Fomin (USA), I. Gessel (USA),
C. Greene (USA), A. Hamel (England), D. Kim (Korea),
C. Krattenthaler (Austria), D. Krob (France), M. Noy (Spain), V. Reiner (USA),
C. Reutenauer (UQAM), F. Sottile (U. Toronto), T. Visentin (U. Winnipeg).
M. Wachs (USA), H. Yamada (Japan), G. Ziegler (Germany).

PARTICIPANT SUPPORT: Limited funds are available for partial support of
participants. Requests should contain a letter of recommendation and
include the estimated transportation and living expenses as well as the
amount of support available from other sources. All requests should be sent
in duplicate by January 15, 1998 to the following address :

Walter Whiteley, Organizing committee of FPSAC '98
Department of Mathematics and Statistics 61
York University
4700 Keele St.
North York, Ontario, Canada, M3J 1P3.

whiteley(at-sign)mathstat.yorku.ca

LOCATION: The conference will take place at the Fields Institute in
Toronto, Canada. The first talk is scheduled on June 15, 1998 at 9:00 a.m.

FURTHER INFORMATION: A WWW site

http://www.math.yorku.ca/bergeron

has been set up for the conference which will always contain the latest state
of affairs. For any further question, just write to

bergeron(at-sign)mathstat.yorku.ca.

ORGANIZING COMMITTEE
N. Bergeron, Chairman (York U.), M. Delest (U. de Bordeaux),
F. Sottile (U. Toronto), W. Whiteley (York U.).

Nantel Bergeron                                   bergeron(at-sign)mathstat.yorku.ca
Associate Prof. Mathematics                          nantel(at-sign)math.harvard.edu
York University                                         nantel(at-sign)lacim.uqam.ca
http://www.math.yorku.ca/bergeron


Date:           Wed, 10 Sep 1997 18:37:45 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu


Combinatorics seminar update:

Date: Friday, Sept. 12, 1997
Title: Arithmetical matchings
Abstract:

Our goal is to generalize the following known matching property of
lattices as far as possible to an arbitrary abelian group.  Let G be a
lattice (discrete additive subgroup of R^n).  Suppose we
are given m lattice points and m direction vectors from G.  Then it is
possible to pair the lattice points with the direction vectors in
one-to-one fashion so that the sum within each pair is not one of the
given lattice points; moreover, this can be done in such a way that
the pairing is uniquely determined by the lattice points, direction
vectors and multiset of sums.

After discussing two approaches to proving the lattice formulation (one
due jointly to Alon, Fan, Kleitman and Losonczy), we describe how the
Dyson e-transform, the Cauchy-Davenport inequality and other tools from
additive number theory can be used to prove the existence of admissible
pairings (matchings) in a more general setting.

Preprint:  http://www-math.mit.edu/~combin


Date:           Fri, 12 Sep 1997 11:22:22 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date: Friday, Sept. 12, 1997
Title: Arithmetical matchings
Preprint: http://www-math.mit.edu/~combin
Abstract:
Our goal is to generalize the following known matching property of
lattices as far as possible to an arbitrary abelian group.  Let G be a
lattice (discrete additive subgroup of $R^n$).  Suppose we
are given m lattice points and m direction vectors from G.  Then it is
possible to pair the lattice points with the direction vectors in
one-to-one fashion so that the sum within each pair is not one of the
given lattice points; moreover, this can be done in such a way that
the pairing is uniquely determined by the lattice points, direction
vectors and multiset of sums.

After discussing two approaches to proving the lattice formulation (one
due jointly to Alon, Fan, Kleitman and Losonczy), we describe how the
Dyson e-transform, the Cauchy-Davenport inequality and other tools from
additive number theory can be used to prove the existence of admissible
pairings (matchings) in a more general setting.

Upcoming events:

Date:  Wednesday, Sept. 17, 1997
Speaker: Igor Pak (MIT/Yale)
Title: Ribbon Tile Invariants

Date:  Friday, Sept. 19, 1997
Title: Brauer diagrams, updown tableaux and conjugacy classes  of
nilpotent  matrices

Date:  Wednesday, Sept. 24, 1997
Speaker: Alexander Kirillov
Title: Kazhdan-Lusztig polynomials and canonical basis

Date:  Friday, Sept. 26, 1997
Speaker: Alex Postnikov
Title: Hidden symmetries of Gromov-Witten invariants



Date:           Tue, 16 Sep 1997 13:29:50 -0400 (EDT)
From:           Jim Propp <propp(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        M.I.T. combinatorics seminar: upcoming talks


UPCOMING MIT COMBINATORICS SEMINARS:

Ribbon Tile Invariants

Igor Pak (MIT)

Room 2-338

---->  16:15, Wednesday, September 17, 1997  <---- * tomorow! *

Consider the problem of tiling a region on a square grid by a given set of
tiles.  You can use the same tile many times, but only translations are allowed
(no rotations or reflections).  There are two types of questions you can ask:

(1) Are there any tilings of a given region?
(2) If there are, what do these tilings look like?

While most people were traditionally concerned with the first question, in
our work we are dealing with the second question.  Namely, in a case of ribbon
tiles (also called rim hooks in a different context) we were able to find all
the affine linear relations for the number of times each tile can occur in a
tiling.  This generalizes the Conway-Lagarias Theorem and explains certain
results regarding characters of the symmetric groups.

The crucial part of the proof is the Stanton-White bijection and its
generalization.  We also give some applications to tileability (the first
question).

Brauer Diagrams, Updown Tableaux and Conjugacy Classes of Nilpotent Matrices

Professor Itaru Terada (University of Tokyo)

Room 2-338

16:15, Friday, September 19, 1997

We give a geometric interpretation of S. Sundaram's correspondence, or the
one modified by T. Roby, between the Brauer diagrams on 2n points and the
updown tableaux of length 2n which both start and end at the empty shape.

Our interpretation is an analogue of R. Steinberg's result on the original
Robinson-Schensted correspondence, which describes the relative position of
a generic pair of complete flags fixed by a unipotent transformation and
having a prescribed pair of sequences of types under it.

Our result uses pairs of a nondegenerate symplectic form and a complete flag
instead of pairs of complete flags, and has been inspired by works by Oshima
and Matsuki on orbit decompositions of symmetric spaces.

Kazhdan-Lusztig Polynomials and Canonical Bases

Alexander Kirillov (MIT)

Room 2-338

16:15, Wednesday, September 24, 1997

We show that the Kazhdan-Lusztig polynomials (and, more generally, parabolic
KL polynomials) for the group S_n coincide with the coefficients of the
canonical basis in the nth tensor power of the fundamental representation of
the quantum group U_q SL_k.  We also use known results about canonical bases
for U_q SL_2 to get a new, simple proof of the recurrent formulas for KL
polynomials for maximal parabolic subgroups (geometrically, this case
corresponds to Grassmanians), due to Lascoux-Schutzenberger and Zelevinsky.
This is joint work with I. Frenkel and M. Khovanov.

Hidden Symmetries of Gromov-Witten Invariants

Alex Postnikov (MIT)

Room 2-338

16:15, Friday, September 26, 1997

Gromov-Witten invariants of flag manifolds generalize the intersection numbers
of Schubert varieties (aka Littlewood-Richardson coefficients).  Their study
and explicit calculation is an important problem in quantum Schubert calculus.
The aim of the talk is to present certain symmetries of these invariants under
the action of cyclic groups.  This allows one to calculate 1/n of all these
invariants.


Date:           Fri, 19 Sep 1997 11:44:04 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date:  Friday, Sept. 19, 1997
Speaker: Prof. Itaru Terada (University of Tokyo)
Title: Brauer diagrams, updown tableaux and conjugacy classes  of
nilpotent  matrices

We give a geometric interpretation of S. Sundaram's correspondence,
or the one modified by T. Roby, between the Brauer diagrams on 2n
points and the updown tableaux of length 2n which both start and
end at the empty shape.

Our interpretation is an analogue of R. Steinberg's result on the
original Robinson-Schensted correspondence, which describes the
relative position of a generic pair of complete flags fixed by a
unipotent transformation and having a prescribed pair of sequences of
types under it.

Our result uses pairs of a nondegenerate symplectic form and a
complete flag instead of pairs of complete flags, and has been
inspired by works by Oshima and Matsuki on orbit decompositions of
symmetric spaces.

Date:  Wednesday, Sept. 24, 1997
Speaker: Alexander Kirillov
Title: Kazhdan-Lusztig polynomials and canonical basis

Date:  Friday, Sept. 26, 1997
Speaker: Alex Postnikov
Title: Hidden symmetries of Gromov-Witten invariants



Date:           Wed, 24 Sep 1997 13:59:17 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date:  Wednesday, Sept. 24, 1997
Speaker: Alexander Kirillov
Title: Kazhdan-Lusztig polynomials and canonical basis
Abstract:
We show that the Kazhdan-Lusztig polynomials
(and, more generally, parabolic KL polynomials) for the group
S_n coincide with the coefficients of the canonical basis in the
nth tensor power of the fundamental representation of the
quantum group <it>U_q SL_k</it>.  We also use known results about canonical
bases for <it>U_q SL_2</it> to get a new, simple proof of the recurrent
formulas for KL polynomials for maximal parabolic subgroups
(geometrically, this case corresponds to Grassmanians), due to
Lascoux-Schutzenberger and Zelevinsky. This is joint work with
I. Frenkel and M. Khovanov.

Date:  Friday, Sept. 26, 1997
Speaker: Alex Postnikov
Title: Hidden symmetries of Gromov-Witten invariants

Date: Wednesday, October 1, 1997
**Holiday--No seminar**

Date:  Friday, October 3, 1997
Speaker: Peter Magyar (Northeastern University)
Title:

Date:  Wednesday, October 8, 1997
Speaker:  Irena Peeva(MIT)
Title: Resolving a monomial ideal by a simplicial complex

Date:  Friday, October 10, 1997
**Holiday--No seminar**



Date:           Fri, 26 Sep 1997 13:11:55 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date:  Friday, Sept. 26, 1997
Speaker: Alex Postnikov
Title: Hidden symmetries of Gromov-Witten invariants
Abstract:
Gromov-Witten invariants of flag manifolds generalize the intersection
numbers of Schubert varieties (aka Littlewood-Richardson
coefficients).  Their study and explicit calculation is an important
problem in quantum Schubert calculus.  The aim of the talk is to
present certain symmetries of these invariants under the action of
cyclic groups.  This allows one to calculate 1/n of all these
invariants.

Date: Wednesday, October 1, 1997
**Holiday--No seminar**

Date:  Friday, October 3, 1997
Speaker: Peter Magyar (Northeastern University)
Title:

Date:  Wednesday, October 8, 1997
Speaker:  Irena Peeva(MIT)
Title: Resolving a monomial ideal by a simplicial complex

Date:  Friday, October 10, 1997
**Holiday--No seminar**



Date:           Wed, 1 Oct 1997 16:01:57 -0400 (EDT)
From:           Jim Propp <propp(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        New URL


The URL for the archives of the MIT Combinatorics Seminar is now
http://www-math.mit.edu/~combin/archive/

Jim Propp


Date:           Fri, 3 Oct 1997 10:18:13 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

For each partition with parts less than n, there is a variety of
partial flags of subspaces in an n-dimensional vector space.  We use
V. Kac's method of quiver representations to answer the question: For
which tuples of partitions does the group $GL(n)$ act on the
corresponding product of partial flag varieties with finitely many
orbits?  (For a single flag variety, these orbits are Schubert cells.)
We describe the poset (Bruhat order) given by closures of these
orbits.  Joint work with J. Weyman and A. Zelevinsky.

Date:  Wednesday, October 8, 1997
Speaker:  Irena Peeva(MIT)
Title: Resolving a monomial ideal by a simplicial complex

Date:  Friday, October 10, 1997
**Holiday--No seminar**

Date:  Friday, October 17, 1997
Speaker: Bernd Sturmfels  (RIMS Kyoto and UC Berkeley)
Title: Groebner deformations of A-hypergeometric equations

Date:  Wednesday, October 22, 1997
Speaker: Mark Haiman (UCSD)
Title: To Be Announced



Date:           Fri, 3 Oct 1997 11:37:01 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today (again)


Woops, it was pointed out that I left out some important information
in my last message.

*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date:  Friday, October 3, 1997
Speaker: Peter Magyar (Northeastern University)
Title: Bruhat order on quiver varieties

For each partition with parts less than n, there is a variety of
partial flags of subspaces in an n-dimensional vector space.  We use
V. Kac's method of quiver representations to answer the question: For
which tuples of partitions does the group $GL(n)$ act on the
corresponding product of partial flag varieties with finitely many
orbits?  (For a single flag variety, these orbits are Schubert cells.)
We describe the poset (Bruhat order) given by closures of these
orbits.  Joint work with J. Weyman and A. Zelevinsky.

Date:  Wednesday, October 8, 1997
Speaker:  Irena Peeva(MIT)
Title: Resolving a monomial ideal by a simplicial complex

Date:  Friday, October 10, 1997
**Holiday--No seminar**

Date:  Friday, October 17, 1997
Speaker: Bernd Sturmfels  (RIMS Kyoto and UC Berkeley)
Title: Groebner deformations of A-hypergeometric equations

Date:  Wednesday, October 22, 1997
Speaker: Mark Haiman (UCSD)
Title: To Be Announced



Date:           Wed, 8 Oct 1997 13:50:38 -0400 (EDT)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date:  Wednesday, October 8, 1997
Speaker:  Irena Peeva(MIT)
Title: Resolving a monomial ideal by a simplicial complex
Preprint: http://www-math.mit.edu/~combin/preprints/Peeva97.ps

This is a joint work with Dave Bayer (Columbia Univ) and
Bernd Sturmfels (Univ of California, Berkeley).

Let M be a monomial ideal in  the polynomial ring
S=k[x_1,... ,x_n] over a field k. We are interested
in the problem, first posed by Kaplansky in the early 1960's,
of finding a minimal free resolution of  S/M over S.
The difficulty of this problem is reflected in the fact that
the homology of arbitrary simplicial complexes can be encoded
via the Stanley-Reisner correspondence into the multigraded
Betti numbers of S/M.  In particular, the minimal
free resolution may depend on the characteristic of k.

We introduce an approach of resolving by encoding the whole
resolution (including the differential maps) into a single
simplicial complex. We prove that generically such a resolution
is minimal and comes from the boundary of a polytope. We
resolve (non-minimally) an arbitrary monomial ideal by
deforming it to a generic one.

Background: I will assume familiarity with Section 11 in
Chapter I in the book "Combinatorics and commutative algebra"
by R. Stanley.

Upcoming events:

Date:  Friday, October 10, 1997
**Holiday--No seminar**

Date:  Wednesday, October 15, 1997
No Seminar

Date:  Friday, October 17, 1997
Speaker: Bernd Sturmfels  (RIMS Kyoto and UC Berkeley)
Title: Groebner deformations of A-hypergeometric equations
Preprint: http://www-math.mit.edu/~combin/preprints/Sturmfels97.ps

Date:  Wednesday, October 22, 1997
Speaker: Mark Haiman (UCSD)
Title: Macdonald polynomials, Hilbert Schemes and the $n$-Factorial Conjecture

Date:  Friday, October 24, 1997
Speaker: Venkat Lakshmibai (Northeastern University)
Title: Tangent Spaces to Schubert Varieties

Date:  Wednesday, October 29, 1997
Speaker: Open Mike Day
Title: (hosted by Jim Propp)

Date:  Friday, October 31, 1997
Speaker: Robin PEMANTLE
Title: Linear recursions in two variables


Date:           Thu, 9 Oct 1997 14:01:20 -0400 (EDT)
From:           Richard Stanley <rstan(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        [WEYMAN(at-sign)neu.edu: Buchsbaum Conference Schedule and Directions.]


------- Start of forwarded message -------

Dear Combinatorialists,

Here is some information on a meeting to be held soon at Northeastern
University that might be of interest. It is a conference in honor of
David Buschsbaum.

Richard
___________________________________________________________________

Saturday, 18 October, 105 New Classroom Building

9:00-9:50  J. Green, Discrete series characters for GL(n,q),
coffee
10:30-11:20  W. Fulton, Chern class formulas for degeneracy loci,
lunch
1:30-2:20 M. Ringel, Quasihereditary algebras and their $\Delta$-good modules
tea
3:00-3:50 G-C. Rota, Invariants under translation,

4:20-4:40 P. Freyd, TBA,
4:50-5:10 M. Klucznik, Letterplace techniques in representation theory of
general linear group,
5:30-5:50 H-B. Foxby, Auslander-Buchsbaum Equalities and Restricted
Tor-dimension,

dinner at 7,  at the Thai restaurant Sawasdee, 320 Washington St.,
Brookline, cost at approximately $25. Graduate students will be subsidized. Sunday, 19 October, 105 New Classroom Building 9;00-9:50 A. Lascoux, Classes of determinantal varieties and Postulation, coffee 10:30-11:20V. Lakshmibai,Schubert varieties - their relationship to toric varities,ladder determinantal varieties and quivers, 11:50-12:40 M. Haiman, Macdonald polynomials and Hilbert schemes, lunch 2:30-3:20 C. DeConcini, On the cohomology of Artin groups, tea 3:50-4:40 B. Sturmfels, Combinatorial Resolutions. 5:00 poster session. Monday 20 October, 320, Curry Student Center 9:00-9:50 K. Akin, The resolutions of determinantal varieties and superalgebra coffee 10:30-11:20 H. Srinivasan, A Question on Determination lunch 1:30-2:20 R. Stanley, Characteristic polynomials of hyperplane arrangements, tea 3:00-3:50 A. Zelevinsky, Multiple flag varieties of finite type, 4:20-4:40 D. Leites, Quivers and Lie superalgebras, 4:50-5:10 M. Hashimoto, Buchsbaum-Rim type resolutions of determinantal ideals, 5:20-5:40 S. Kleiman, Conormal geometry of maximal minors. Directions: To get to the New Classroom Building just follow the Forsyth Street from the crossing of Huntington Av. with Forsyth Street ( one block from Museum of Fine Arts ) into the campus. After passing the crossing with Greenleaf Street, this is the second building on the right. The room 105 is on the first floor, on the right side of the building. The parking garage is located in Columbus Av., you should turn right from Massachusetts Av. into Columbus Av. ( if you are coming from Symphony Hall ) and the parking garage is located 2 blocks away, on the right side. The best access by Green line is to walk from the Auditorium Station. You walk along Massachsetts Avenue, towards Symphony Hall and turn right to Huntington Avenue. Then walk two blocks to come to the crossing with Forsyth Street. In the case of rain, another possibility ( longer but involving no walking ) is to go to Arlington Station, then taking part E of the green line outbound which has a stop on the corner of Huntington Av. and Forsyth St. If you come by orange line, come to the Ruggles Station. As you leave the station towards Northeastern campus, you see the New Classroom Building in front of you. If you arrive on Friday, you are welcome to come to the Department on Friday late afternoon. The organizers will be there, we plan to go to an informal dinner to a nearby restaurant with all people that arrive, at about 7PM. The Department is located in Lake Hall ( the building at the corner of Forsyth Street and Greenleaf Street ). Turn to Greenleaf Street to find the entrance "Lake Hall" and go to the 4-th floor. The offices of Alex M. and Jerzy W. are located there. Please let me know if there are any problems. Best regards. Jerzy Weyman. ------- End of forwarded message -------  Date: Wed, 15 Oct 1997 12:59:26 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: no seminar today  There is no combinatorics seminar today. The seminar schedule is now booked every Wednesday and Friday for the entire semester (except for today and the day before Thanksgiving). Below is the schedule for the next few weeks of talks. Please note that several preprints are available on our web page. See you Friday. Date: Friday, October 17, 1997 Speaker: Bernd Sturmfels (RIMS Kyoto and UC Berkeley) Title: Groebner deformations of A-hypergeometric equations **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Wednesday, October 22, 1997 Speaker: Mark Haiman (UCSD) Title: Macdonald polynomials, Hilbert Schemes and the$n$-Factorial Conjecture Date: Friday, October 24, 1997 Speaker: Venkat Lakshmibai (Northeastern University) Title: Tangent Spaces to Schubert Varieties Date: Wednesday, October 29, 1997 Speaker: Open Mike Day Title: (hosted by Jim Propp) Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/  Date: Fri, 17 Oct 1997 11:55:54 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, October 17, 1997 Speaker: Bernd Sturmfels (RIMS Kyoto and UC Berkeley) Title: Groebner deformations of A-hypergeometric equations **Preprint Available*** http://www-math.mit.edu/~combin/ We apply Groebner basis theory to study the A-hypergeometric system of differential equations which was defined by Gel'fand, Kapranov and Zelevinsky for any lattice configuration A. This system is holonomic; its rank equals vol(A) if the toric ideal of A is Cohen-Macaulay or if the parameters are generic, but its rank may exceed vol(A) otherwise. To bound the rank and to construct series solutions for all parameters values, we introduce the initial ideal of the A-hypergeometric system with respect to a suitable term order. The initial ideal contains the ideal of indicial polynomials (in the sense of Frobenius), and they are equal generically. Our goal is to determine all solutions of the indicial ideal and to identify which ones arise from A-hypergeometric series. In this talk we present results for the case when the underlying triangulation of A is unimodular. This is joint work in progress with Nobuki Takayama (Kobe) and Mutsumi Saito (Sapporo). Date: Wednesday, October 22, 1997 Speaker: Mark Haiman (UCSD) Title: Macdonald polynomials, Hilbert Schemes and the$n$-Factorial Conjecture Date: Friday, October 24, 1997 Speaker: Venkat Lakshmibai (Northeastern University) Title: Tangent Spaces to Schubert Varieties Date: Wednesday, October 29, 1997 Speaker: Open Mike Day Title: (hosted by Jim Propp) Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/  Date: Fri, 17 Oct 1997 15:23:06 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: changes  It has just come to my attention that several people are interested in attending both the combinatorics seminar and the algebraic geometry seminar today. Therefore, we have decided to combine the two seminars and have each person speak for 45 mins. In order to accommodate both audiences we will start at 4:00 and we have gotten a bigger classroom *4-163*. 4:00 Keith Pardue (Queen's University) What can be preserved under deformation? 4:45 Bernd Sturmfels (RIMS Kyoto and UC Berkeley) Groebner deformations of A-hypergeometric equations Below is Pardue's abstract: Hartshorne proved in his thesis that subschemes of projective space may be deformed to one another if and only if they have the same Hilbert polynomial. These deformations may be realized as sequences of deformations over projective lines. If the subschemes have more properties in common, then can these properties be preserved while performing the deformations? I show that certain properties, including the Hilbert functions and the depths of the subschemes, can be preserved while deforming one to the other, with the deformations realized as sequences of deformations over affine lines. In particular, an arithmetically Cohen-Macaulay subscheme of projective space may be deformed to any other arithmetically Cohen-Macaulay subscheme of projective space having the same Hilbert function, with all of the fibers of the deformations being arithmetically Cohen-Macaulay with the same Hilbert function. I prove similar theorems for deformations of finitely generated graded modules over a polynomial ring.  Date: Sun, 19 Oct 1997 14:28:40 -0400 (EDT) From: Jim Propp <propp(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: Oct. 29: Open Mike  This is a reminder that the Wednesday, October 29 meeting of the MIT Combintorics Seminar will be an "open mike" session. To make things run as smoothly as possible, all those who are interested in making a short presentation at this session should contact me (propp(at-sign)math.mit.edu) ahead of time. Jim Propp  Date: Tue, 21 Oct 1997 15:56:54 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: Special seminar  Two things: 1) Mark Haiman will be speaking tomorrow in the combinatorics seminar. Anyone who wants go to lunch with him can meet at my office at 12:30. We will go to the faculty lunch on the second floor of Walker. 2) We will have a special seminar on Thursday at 3:00pm in 2-338 that should be interesting to combinatorialists: Speaker: Alain Lascoux Title: Bruhat order on finite Coxeter groups Abstract: Bruhat order on Coxeter groups is usually defined by considering subwords of reduced decompositions. With M.P. Schutzenberger, I obtain a decomposition of the order by embedding the group into a lattice. In the case of the symmetric group, the lattice is distributive, and its vertices can be identified with the alternating sign matrices.  Date: Tue, 21 Oct 1997 20:05:59 -0400 (EDT) From: G-C Rota <rota(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: something to share with you.  I am happy to inform you that our former student William Y.C.Chen has just been awarded a big international prize. Here is the message I just got: Dear Gian-Carlo, Good news -- I just learned that I got the Javed Jusain Prize. Thank you so much for your support and for your strategy. Things are going very well here. I will report to you in more detail later. I am in a rush (the building is being closed [at a regular hour]), and will write to you later. Thanks again. Bill  Date: Wed, 22 Oct 1997 13:34:51 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Wednesday, October 22, 1997 Speaker: Mark Haiman (UCSD) Title: Macdonald polynomials, Hilbert Schemes and the$n$-Factorial Conjecture Abstract: I'll give an introduction to certain easily defined spaces which have remarkable conjectured combinatorial interpretations. The conjectures have turned out to be surprisingly difficult, and it has gradually become clear that there is some fundamental algebraic geometry behind them, involving the Hilbert scheme of points in the plane, which I'll briefly explain. Upcoming Events: Date: Friday, October 24, 1997 Speaker: Venkat Lakshmibai (Northeastern University) Title: Tangent Spaces to Schubert Varieties Date: Wednesday, October 29, 1997 Speaker: Open Mike Day Title: (hosted by Jim Propp) Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables  Date: Fri, 24 Oct 1997 10:03:09 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu, combinatorics(at-sign)euclid.ucsd.edu Subject: Conference Announcement (text and latex)   ICM 1998 Satellite Conference Representations of finite groups and combinatorics'' August 10-14, 1998 Magdeburg, Germany First Announcement This is a satellite conference to the ICM 1998 taking place at the Otto-von-Guericke University of Magdeburg, located about 150 km west of Berlin; it focuses on those areas of representation theory of finite groups which have strong connections with combinatorics, the related combinatorics of partitions and tableaux, the theory of symmetric functions, and related areas. The program will be scheduled from Monday morning to Friday evening, with arrival on Sunday, August 9, and departure on Saturday, August 15. Organizers: C. Bessenrodt (Magdeburg), A. O. Morris (Aberystwyth), J. B. Olsson (Copenhagen). At present, the following principal speakers have accepted the invitation: Karin Erdmann (Oxford, Great Britain) Phil Hanlon (Ann Arbor, USA) Gordon James (London, Great Britain) Alexander Kleshchev (Eugene, USA) Peter Littelmann (Strasbourg, France) Ian Macdonald (London, Great Britain) Gunter Malle (Heidelberg, Germany) Bhama Srinivasan (Chicago, USA) Richard Stanley (Boston, USA) In addition to the one hour lectures by the principal speakers it is planned to have further talks by the participants on the following topics: Representation theory of symmetric and related groups Representations of finite groups of Lie type Representations of Hecke algebras and q-Schur algebras Combinatorics of partitions and tableaux New combinatorial concepts for studying representations Symmetric functions Relations to other areas, such as invariant theory and physics Accommodation: There are a limited number of guest rooms on campus, and hotels within walking distance. Registration: Please preregister, preferably by email, until the end of 1997; due to space restrictions the number of participants will be limited. Early 1998 we will send out further information such as a hotel list, registration form etc. Conference fee: 80 DM We plan to create a website for the conference with up-to-date information; please check the homepage for the ICM 98 http://elib.zib.de/ICM98 for the link to this website. Contact Address: ICM Satellite Conference Institut f"ur Algebra und Geometrie Fakult"at f"ur Mathematik Otto-von-Guericke-Universit"at Magdeburg D-39016 Magdeburg, Germany email: icmsat98(at-sign)uni-magdeburg.de -------------- latex-file -------------------------------------- \documentstyle[12pt]{article} \setlength{\oddsidemargin}{0cm} \setlength{\headheight}{0pt} \setlength{\headsep}{0pt} \setlength{\textheight}{23cm} \setlength{\textwidth}{16cm} \parindent=0cm \begin{document} \begin{center} {{\large \sc ICM 1998 Satellite Conference}\\[1ex] \Large \bf Representations of finite groups and combinatorics''\\[1ex] \large \bf August 10-14, 1998 \\ Magdeburg, Germany\\[1ex] First Announcement} \end{center} \vspace{2ex} This is a satellite conference taking place at the Otto-von-Guericke University of Magdeburg, located about 150 km west of Berlin; it focuses on those areas of representation theory of finite groups which have strong connections with combinatorics, the related combinatorics of partitions and tableaux, the theory of symmetric functions, and related areas. \vspace{2ex} The program will be scheduled from Monday morning to Friday evening, with arrival on Sunday, August 9, and departure on Saturday, August 15. \vspace{2ex} {\bf Organizers}:\\ C.\ Bessenrodt (Magdeburg), A.~O.\ Morris (Aberystwyth), J.~B.\ Olsson (Copenhagen).\\ \vspace{2ex} At present, the following {\bf principal speakers} have accepted the invitation: \begin{center} \parbox[t]{10cm}{ Karin Erdmann (Oxford, Great Britain)\\ Phil Hanlon (Ann Arbor, USA)\\ Gordon James (London, Great Britain)\\ Alexander Kleshchev (Eugene, USA)\\ Peter Littelmann (Strasbourg, France)\\ Ian Macdonald (London, Great Britain)\\ Gunter Malle (Heidelberg, Germany)\\ Bhama Srinivasan (Chicago, USA)\\ Richard Stanley (Boston, USA)} \end{center} In addition to the one hour lectures by the principal speakers it is planned to have further talks by the participants on the following topics: \begin{center} \parbox[t]{13cm}{ Representation theory of symmetric and related groups\\ Representations of finite groups of Lie type\\ Representations of Hecke algebras and$q$-Schur algebras \\ Combinatorics of partitions and tableaux \\ New combinatorial concepts for studying representations \\ Symmetric functions \\ Relations to other areas, such as invariant theory and physics} \end{center} \vspace{1ex} {\bf Accommodation:} There are a limited number of guest rooms on campus, and hotels within walking distance. \\ {\bf Registration:} Please preregister, preferably by email, until the end of 1997; due to space restrictions the number of participants will be limited. Early 1998 we will send out further information such as a hotel list, registration form etc. \\ {\bf Conference fee:} 80 DM \\ We plan to create a website for the conference with up-to-date information; please check the homepage for the ICM 98 \centerline{\bf http://elib.zib.de/ICM98} for the link to this website. \\ {\bf Contact Address:} \\ ICM Satellite Conference \\ Institut f\"ur Algebra und Geometrie\\ Fakult\"at f\"ur Mathematik\\ Otto-von-Guericke-Universit\"at Magdeburg\\ D-39016 Magdeburg, Germany \\ {\bf email:} icmsat98(at-sign)uni-magdeburg.de \end{document}  Date: Fri, 24 Oct 1997 10:16:07 -0400 (EDT) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: Seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, October 24, 1997 Speaker: V. Lakshmibai (Northeastern University) Title: Tangent Spaces to Schubert Varieties Abstract: Let G be a classical group, T a maximal torus in G, and B a Borel sub group containing T. Let X be any Schubert variety in G/B, and let v be any T-fixed point in X. We give an explicit description of the tangent space to X at v. Upcoming events: Date: Wednesday, October 29, 1997 Speaker: Open Mike Day Title: (hosted by Jim Propp) Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces Date: Wednesday, November 19, 1997 Speaker: Sara Billey (MIT) Title: Pattern Avoidance and Rational Smoothness of Schubert Varieties Date: Friday, November 21, 1997 Speaker: Christos Athanasiadis Title: Projections of cyclic polytopes and their fiber polytopes Date: Wednesday, November 26, 1997 **Holiday--No seminar** Date: Friday, November 28, 1997 **Holiday--No seminar**  Date: Fri, 24 Oct 1997 20:27:47 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins)   Come to the Twenty-seventh one day conference on Combinatorics and Graph Theory Saturday, November 15, 1997 10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063 Schedule 10:00 Katalin Vesztergombi (Yale University) Properties of Distance-Graphs 11:10 Charles Colbourn (Univ. of Vermont) Group Testing and Weakly Union-free Designs 12:30 Lunch 2:00 Joel Spencer (New York University--Courant Institute) Sixty Years of Ramsey R(3,k) 3:10 Dan Rockmore (Dartmouth College) TBA The conferences are supported by an NSF grant which allows us to provide a modest transportation allowance to those attendees who are not local. We also gratefully acknowledge support from Smith College and Wesleyan University. Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html Michael Albertson (Smith College), (413) 585-3865, albertson(at-sign)math.smith.edu Karen Collins (Wesleyan University), (860) 685-2169, kcollins(at-sign)wesleyan.edu Ruth Haas (Smith College), (413) 585-3872, rhaas(at-sign)math.smith.edu  From: elias(at-sign)theory.lcs.mit.edu (Peter Elias) Date: Wed, 29 Oct 97 11:16:54 EST To: eecsfaculty(at-sign)eecs.mit.edu, seminars(at-sign)lcs.mit.edu, ai-tech-sq(at-sign)ai.mit.edu, joanne(at-sign)theory.lcs.mit.edu, sgreen(at-sign)ll.mit.edu, jsweeney(at-sign)draper.com, young(at-sign)lids.mit.edu, msgs(at-sign)media.mit.edu, jc(at-sign)cs.brandeis.edu, texasgal(at-sign)MIT.EDU, bru(at-sign)media.mit.edu, arthurs(at-sign)MIT.EDU, dougross(at-sign)MIT.EDU, msgs(at-sign)media.mit.edu, rpindyck(at-sign)MIT.EDU, or_faculty(at-sign)MIT.EDU, combinatorics(at-sign)math.mit.edu Subject: EECS Colloquium November 3  Please forward and/or post as appropriate. ---------------------------------------------------------------------- FACTOR GRAPHS AND ALGORITHMS: CONNECTING BELIEF PROPAGATION TO THE FFT AND TURBO DECODING Frank Kschischang University of Toronto, visiting EECS and RLE Abstract A "factor graph" is a bipartite graph that expresses how a global function of several variables factors into a product of "local functions". In this talk, I will describe a general algorithm for computing "marginals" of the global function by distributed message-passing in the corresponding factor graph. A wide variety of algorithms developed in the artificial intelligence, statistics, signal processing, and digital communications communities can be derived as specific instances of this general algorithm, including Pearl's "belief propagation" algorithm, the Fast Fourier transform, the Viterbi algorithm, the forward/backward algorithm, and the iterative turbo decoding algorithm. November 3, 1997 4-5 pm refreshments 3:45 Edgerton Hall, (MIT room Room 34-101, 50 Vassar St.) ======================================================================  Date: Wed, 29 Oct 1997 13:26:39 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Wednesday, October 29, 1997 Title: Open Mike Day Speaker: (hosted by Jim Propp) Any and all combinatorialists are invited to prepare a short 5-15 minute presentation on a resent result or open problem. Those who are interested in speaking should send e-mail to Jim Propp (propp(at-sign)math.mit.edu) ahead of time. Hopefully, everyone who wants to speak will get a chance. Upcoming events: Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces  From: Sara Billey <sara(at-sign)math.mit.edu> Date: Fri, 31 Oct 1997 10:53:17 -0500 (EST) To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, October 31, 1997 Speaker: Robin PEMANTLE Title: Linear recursions in two variables Let a(i,j) be real numbers for i , j > 0, satisfying a recursion Sum a(i-r,j-s) c(r,s) = 0 for all but finitely many (i,j), where phi (x,y) := Sum c(r,s) x^r y^s is a given polynomial. The problem of determining asymptotics for a(i,j) is more complicated than in the one variable case for two reasons. First, in the case where phi(0,0) = 0, the generating function is not rational, and some care is needed in obtaining it. Secondly, obtaining asymptotics from the generating function is not nearly so straightforward as it is in the one variable case. I will discuss both these problems, give examples, some motivation, and partial solutions. This is work in progress. Upcoming Events: Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces  Date: Sat, 1 Nov 1997 09:18:33 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins) Subject: November 15, second announcement   Come to the Twenty-seventh one day conference on Combinatorics and Graph Theory Saturday, November 15, 1997 10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063 Schedule 10:00 Katalin Vesztergombi (Yale University) Properties of Distance-Graphs 11:10 Charles Colbourn (Univ. of Vermont) Group Testing and Weakly Union-free Designs 12:30 Lunch 2:00 Joel Spencer (New York University--Courant Institute) Sixty Years of Ramsey R(3,k) 3:10 Dan Rockmore (Dartmouth College) FFTs for$SL_2(F_q)$- Theory and Applications The conferences are supported by an NSF grant which allows us to provide a modest transportation allowance to those attendees who are not local. We also gratefully acknowledge support from Smith College and Wesleyan University. Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html Michael Albertson (Smith College), (413) 585-3865, albertson(at-sign)math.smith.edu Karen Collins (Wesleyan University), (860) 685-2169, kcollins(at-sign)wesleyan.edu Ruth Haas (Smith College), (413) 585-3872, rhaas(at-sign)math.smith.edu  Date: Mon, 3 Nov 1997 14:32:36 -0500 (EST) From: Combinatorics Conference <calca(at-sign)Oakland.edu> To: calca(at-sign)Oakland.edu Subject: Conference Annoucement  ================================================================================================= FIRST ANNOUNCEMENT Conference on Algebraic Combinatorics and Applications Oakland University, Rochester, Michigan May 1-3, 1998 Invited one-hour speakers include Anders Bjorner (Royal Institute of Technology, Stockholm) Robert Calderbank (AT&T Research) Peter Cameron (Queen Mary College, London) Jennifer Chayes (Microsoft) Philippe Flajolet (INRIA) Ronald Graham (AT&T Research) David Jackson (University of Waterloo) Richard Stanley (MIT) There will also be sessions for invited half-hour talks; speakers currently include Georgia Benkart, Nantel Bergeron, Sara Billey, Aart Blokhuis, Aldo Conca, Sergey Fomin, Bernard Leclerc, Victor Reiner, John Stembridge, Neil White and Charles Johnson.. Persons in academia or industry interested in exploring this fertile and evolving area of mathematics and its interactions with and applications to other areas are encouraged to participate. Some support will be available to assist graduate students in attending the conference. Sponsors include the National Science Foundation, the National Security Agency, Oakland University, the Oakland University Foundation, and others still pending. Anyone interested in further information should send name, institution, e-mail address, and current estimated probability of attending, to the organizers by e-mail or snail-mail. Conference e-mail address: calca(at-sign)oakland.edu Conference home page on the World Wide Web: http://www.oakland.edu/~calca Organizing Committee Eddie Cheng (Oakland University) Ian Goulden (University of Waterloo) Jerrold Grossman (Oakland University), Local Arrangements Chair (248) 370-3443 grossman(at-sign)oakland.edu Philip Hanlon (University of Michigan) Devadatta Kulkarni , Director (248) 370-4032 kulkarni(at-sign)oakland.edu Marc Lipman (Oakland University) James McKay (Oakland University) Conference on Algebraic Combinatorics and Applications Department of Mathematical Sciences Oakland University Department of Mathematical Sciences Oakland University Rochester, MI 48309-4485  Date: Mon, 3 Nov 1997 16:17:42 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu, combinatorics(at-sign)euclid.ucsd.edu Subject: [bdt(at-sign)math.wayne.edu: jobs in combinatorics]  Date: Mon, 3 Nov 1997 16:11:06 -0500 From: bdt(at-sign)math.wayne.edu (Brian Taylor) To: sara(at-sign)math.mit.edu Subject: jobs in combinatorics  ------------------------------------------------------------------ The Wayne State University mathematics department is hiring for two tenure-track positions this year. One of these is an open position for which we could hire an algebraic combinatorialist. In particular, the algebra group here is committed to hiring another algebraic combinatorialist within the next several years. Please feel free to ask me unofficial questions about the department or Detroit at "bdt(at-sign)math.wayne.edu". For official information, check our (slightly old) notice on EIMS. Brian Taylor ------------------------------------------------------------------  Date: Wed, 5 Nov 1997 12:55:41 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Wednesday, November 5, 1997 Speaker: James Haglund Title:$q$-Rook polynomials and matrices over finite fields **Preprint Available*** http://www-math.mit.edu/~combin/ Abstract: We start by giving a brief overview of the basics of rook theory and q-rook polynomials. Then we extend a result of Solomon, which shows that q-rook polynomials count the number of matrices over finite fields satisfying certain constraints. This eventually leads to a new statistic for Garsia and Remmel's q-hit polynomial. Both this new statistic "mat" and another statistic for the q-hit polynomial \xi recently introduced by Dworkin are shown to induce different multiset Mahonian permutation statistics for any Ferrers board. In addition, for the triangular boards they are shown to generate different families of Euler-Mahonian statistics. For these boards the \xi family includes Denert's statistic "den", and gives a new proof of Foata and Zeilberger's Theorem that (exc,den) is equi-distributed with (des,maj). The mat family appears to generate a new Euler-Mahonian pair. A proof that the q-hit polynomials are symmetric and unimodal is also discussed. Upcoming Events: Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/ Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces  Date: Fri, 7 Nov 1997 13:03:34 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, November 7, 1997 Speaker: Rod Canfield Title: Maximum Sized Antichains in the Partition Lattice **Preprint Available*** http://www-math.mit.edu/~combin/ Abstract: In 1928 E. Sperner solved this problem: Given a finite ground set S of size n, what is the largest possible collection of subsets of S such that no two of the subsets are related by containment? In the last twenty years, a generalization of this problem has been studied, namely: given a finite partially ordered set (poset), what is its largest antichain? (An antichain is a set of elements no two of which are related by the poset's order relation.) Many interesting posets arise naturally in combinatorics, one of which is partitions of an n-set ordered by refinement. A partition of the n-set [n] = {1,2,...,n} is a collection of pairwise disjoint subsets, called blocks, whose union is [n]. One partition is a refinement of another if the first can be obtained by further partitioning the blocks of the second. Determining the size of the largest antichain in this partition poset has spawned many general theorems in the subject now known as Sperner Theory. We will trace the study of large antichains in the partition lattice. Upcoming Events: Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces  Date: Fri, 7 Nov 1997 18:01:07 -0400 To: Everyone(at-sign)mathstat.yorku.ca From: bergeron(at-sign)mathstat.yorku.ca (Nantel Bergeron) Subject: FPSAC 98 --- SECOND CALL FOR PAPERS  % ********************************************************************** % % % % 10-th international Conference on % % Formal Power Series and Algebraic Combinatorics % % % % June 15-19, 1998 % % Fields Institute, Toronto % % % % First announcement -- Call for papers % % % % ********************************************************************** % TOPICS: Algebraic and bijective combinatorics and their relations with other parts of mathematics, computer science and physics. CONFERENCE PROGRAM: Invited lectures, contributed presentations, poster session, software demonstrations. INVITED SPEAKERS: G. Benkart (USA) P. Cameron (England) (to be confirmed) P. Dehornoy (France) B. Derrida (France) (to be confirmed) P. Diaconis (USA) C. Godsil (Canada) K. Ono (USA) J. Y. Thibon (France) B. Sturmfels (USA) OFFICIAL LANGUAGES: English and French. CALL FOR PAPERS AND POSTERS: Authors are invited to submit extended abstracts of at most twelve pages before November 21, 1997. ------------------ Authors should indicate their choice of presentation appropriate for their paper: lecture or poster session. The preferred method of submission is by sending one postscript file by email to bergeron(at-sign)mathstat.yorku.ca. If an author is not able to send a postscript version of her/his extended abstract, four copies of the extended abstract should be mailed to Nantel Bergeron, Program committee of FPSAC '98 Department of Mathematics and Statistics 61 York University 4700 Keele St. North York, Ontario, Canada, M3J 1P3. The submitted papers should begin with a summary written in the two official languages of the conference (translations will be provided if necessary). The notifications of acceptance or rejection are scheduled for the beginning of March 1998. Published Volume: The authors whose papers will have been accepted for a lecture or a poster presentation will have the possibility to submit a complete version of their work to a special issue of a refereed publication devoted to the conference FPSAC '98. The deadline for submission to the special issue is September 1, 1998. SOFTWARE DEMONSTRATIONS: Demonstrations of software relevant to the topics of the conference are encouraged. People interested in giving a software demonstration should submit a paper as described above, including the hardware requirements, before January 15, 1997, by email to sottile(at-sign)math.toronto.edu. PROGRAM COMMITTEE: I. Goulden, Chairman (Canada), N. Bergeron (Canada), S. Billey (USA), F. Brenti (Italy), R. Cori (France), S. Dulucq (France) K. Eriksson (Sweeden), O. Foda (Australia), S. Fomin (USA/Russia), I. Gessel (USA), C. Greene (USA), A. Hamel (New Zealand), D. Kim (Korea), C. Krattenthaler (Austria), D. Krob (France), M. Noy (Spain), V. Reiner (USA), C. Reutenauer (UQAM), F. Sottile (U. Toronto), T. Visentin (U. Winnipeg). M. Wachs (USA), H. Yamada (Japan), G. Ziegler (Germany). For more Information on registration and support, consult the WWW site http://www.math.yorku.ca/bergeron or email bergeron(at-sign)mathstat.yorku.ca. ORGANIZING COMMITTEE N. Bergeron, Chairman (York U.), M. Delest (U. de Bordeaux), F. Sottile (U. Toronto), W. Whiteley (York U.). Nantel Bergeron bergeron(at-sign)mathstat.yorku.ca Associate Prof. Mathematics nantel(at-sign)math.harvard.edu York University nantel(at-sign)lacim.uqam.ca http://www.math.yorku.ca/bergeron  Date: Tue, 11 Nov 1997 12:59:02 -0400 To: frank sottile <sottile(at-sign)math.utoronto.ca>, combinatorics(at-sign)cs.toronto.edu, combopt(at-sign)math.uwaterloo.ca, combinatorics(at-sign)math.mit.edu, combinatorics(at-sign)euclid.ucsd.edu, everyone(at-sign)mathstat.yorku.ca, deaconu(at-sign)YorkU.CA, JOAQUIN O CARBONARA <CARBONJO(at-sign)BUFFALOSTATE.EDU> From: bergeron(at-sign)mathstat.yorku.ca (Nantel Bergeron) Subject: York U. Applied Algebra Seminar: Y. Medvedev  Announcement: A web page at "http://math.yorku.ca/bergeron" is set up for this new seminar. Please look at it if you are interested. Suggestions are welcome. -------------------------------------------------------------------------- Next week: Applied Algebra Seminar York University Ross Building, North tower: N638R Monday Nov. 17, 1997 3:00 PM -------------------------------------------------------------------------- Compact Periodic and Engel Groups Yuri Medvedev York U. The question whether a compact periodic group has a finite exponent has been known since early 60's. One can find a discussion on this question in the book on Abstract Harmonic Analysis by Hewitt and Ross. Recently, Zelmanov, developing his ideas on the solution of the restricted Burnside problem, has proved that compact periodic groups are locally finite. Hence, every Sylow p-subgroup of compact periodic groups are Engel. I will give an outline of an approach which leads to a necessary and sufficient condition for a periodic compact group to be of finite exponent. It turned out that a periodic compact group has a finite exponent if and only if it is strongly Engel. As usual, we will talk about open problems in this area. -------------------------------------------------------------------------- FORTHCOMING SEMINARS: A. Kirrilov (CRM-St Petersburg) (Nov/Dec) S. Van Willigenburg (York/St Andrews) (Dec) A. Ram (Princeton) (Jan 98) ANY OTHER SUGGESTION? (email me!) Nantel Bergeron bergeron(at-sign)mathstat.yorku.ca Associate Prof. Mathematics nantel(at-sign)math.harvard.edu York University nantel(at-sign)lacim.uqam.ca http://www.math.yorku.ca/bergeron  Date: Wed, 12 Nov 1997 10:12:45 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins) Subject: reminder   Come to the Twenty-seventh one day conference on Combinatorics and Graph Theory Saturday, November 15, 1997 10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063 Schedule 10:00 Katalin Vesztergombi (Yale University) Properties of Distance-Graphs 11:10 Charles Colbourn (Univ. of Vermont) Group Testing and Weakly Union-free Designs 12:30 Lunch 2:00 Joel Spencer (New York University--Courant Institute) Sixty Years of Ramsey R(3,k) 3:10 Dan Rockmore (Dartmouth College) FFTs for$SL_2(F_q)$- Theory and Applications The conferences are supported by an NSF grant which allows us to provide a modest transportation allowance to those attendees who are not local. We also gratefully acknowledge support from Smith College and Wesleyan University. Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html Michael Albertson (Smith College), (413) 585-3865, albertson(at-sign)math.smith.edu Karen Collins (Wesleyan University), (860) 685-2169, kcollins(at-sign)wesleyan.edu Ruth Haas (Smith College), (413) 585-3872, rhaas(at-sign)math.smith.edu  Date: Wed, 12 Nov 1997 15:04:40 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Wednesday, November 12, 1997 Speaker: Steve Fisk Title: Interlacing Polynomials Two polynomials interlace if their roots alternate. The central question in the study of interlacing is When does a linear transformation on the vector space of all polynomials preserve interlacing? In this talk I will discuss various interlacing preserving linear transformations. For instance, differentiation preserves interlacing, but integration does not. It is a classical result that if f and g are polynomials with all real roots then f(D)g has all real roots, where D is differentiation. I will show that the bilinear map sending (f,g) to f(D)g preserves interlacing in each argument. Upcoming Events: Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces  Date: Fri, 14 Nov 1997 12:07:43 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, November 14, 1997 Speaker: Ludwig Danzer (University of Dortmund) Title:Some Theorems About Strictly Ordered but Aperiodic Structures in Euclidean Spaces Let F be a finite set of prototiles T_1, T_2,...,T_k. An F-tiling is a global tiling of euclidean space, where every tile is congruent to some T_{\kappa}. If Infl is an inflation-operator, then S(F,Infl) is the "species" of all F-tilings P such that every bounded cluster of P has a congruent copy in some Infl^n (T_{\kappa}). If LMR is a local matching rule, then S(F, LMR) is the species of all F-tilings which satisfy LMR everywhere. The relationships between the following properties of such species will be discussed: -- (I) being definable by some inflation, -- (D) existence of a unique inverse of Infl, -- (LMR) being definable by some local matching rule, -- (AP) being aperiodic, -- (NL) being non-local (not in contradiction to (LMR) !), -- (R) being repetitive, -- consisting of 2^{\aleph_0} congruence classes. ******************************************************************* The following talk has been rescheduled for February 27: Speaker: Sara Billey (MIT) Title: Pattern Avoidance and Rational Smoothness of Schubert Varieties **Preprint Available*** http://www-math.mit.edu/~sara/ No seminar: Wednesday, November 19, 1997 ******************************************************************* Upcoming events: Date: Friday, November 21, 1997 Speaker: Christos Athanasiadis Title: Projections of cyclic polytopes and their fiber polytopes Date: Wednesday, November 26, 1997 **Holiday--No seminar** Date: Friday, November 28, 1997 **Holiday--No seminar**  Date: Fri, 14 Nov 1997 14:25:29 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins) Subject: cancellation  Smith College is closing today due to a storm depositing sleet, ice and snow on campus. The storm is expected to continue through the weekend. We therefore regret that twenty-seventh CoNE meeting, scheduled for tomorrow, November 15, must be cancelled.  Date: Tue, 18 Nov 1997 15:56:32 -0400 To: bergeron(at-sign)mathstat.yorku.ca From: bergeron(at-sign)mathstat.yorku.ca (Nantel Bergeron) Subject: York U. Applied Algebra Seminar: S. van Willigenburg  Announcement: A web page at "http://math.yorku.ca/bergeron" is set up for this new seminar. Look for our future seminars. Suggestions are welcome. -------------------------------------------------------------------------- Next week: Applied Algebra Seminar York University Ross Building, North tower: N638R Monday Nov. 24, 1997 3:00 PM -------------------------------------------------------------------------- The p-modular descent algebra of the symmetric group Stephanie van Willigenburg (St-Andrews/ York University) Abs: We define the descent algebra of the symmetric group over the rationals. We then extend this definition to a field of finite characteristic. From here we discuss why these structures are of interest, and formulate one of the many open problems in this area. -------------------------------------------------------------------------- FORTHCOMING SEMINARS: N. Bergeron (York) (Dec 1) A. Kirrilov (CRM-St Petersburg) (Dec 8-9) A. Ram (Princeton) (Jan 98) ANY OTHER SUGGESTION? (email me!) Nantel Bergeron bergeron(at-sign)mathstat.yorku.ca Associate Prof. Mathematics nantel(at-sign)math.harvard.edu York University nantel(at-sign)lacim.uqam.ca http://www.math.yorku.ca/bergeron  Date: Wed, 19 Nov 1997 12:05:02 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  There has been a change of plans. There will be a seminar today. *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Wednesday, November 19, 1997 Speaker: J. Maurice Rojas (MIT) Title: The Square Root Volume Conjecture Preprint:http://www-math.mit.edu/~combin/preprints/Rojas97.ps Abstract: Shub and Smale showed that for certain random polynomial systems, the expected number of real roots equals the square root of the expected number of complex roots. We prove a similar theorem for a new family of polynomial systems and propose a broader conjecture --- the square root volume conjecture (SRVC). The class of sparse polynomial systems where the SRVC has been proved also includes randomized versions of the following well-known problems from linear algebra: the generalized eigenvalue problem and the matrix polynomial problem. Our probability measures can all be described via convex geometry, and are natural in a metrically invariant sense, depending on the underlying toric compactification. This talk will be entirely self-contained (no knowledge of toric varieties is assumed). Upcoming Events: Date: Friday, November 21, 1997 Speaker: Christos Athanasiadis Title: Projections of cyclic polytopes and their fiber polytopes Date: Wednesday, November 26, 1997 **Holiday--No seminar** Date: Friday, November 28, 1997 **Holiday--No seminar** December is available at http://www-math.mit.edu/~combin/abstracts.  Date: Wed, 19 Nov 1997 15:42:06 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins) Subject: New meeting!   Come to the (New) Twenty-seventh one day conference on Combinatorics and Graph Theory Saturday, December 13, 1997 10 a.m. to 4:30 p.m. at Smith College Northampton MA 01063 Schedule 10:00 James Lewis (Univ. of Rhode Island) A Collatz Type Difference Equation 11:10 Jeffrey Hall (Univ. of New Hampshire) Applications of Combinatorics to Group Representation Theory 12:10 Lunch 2:00 Charles Colbourn (Univ. of Vermont) Group Testing and Weakly Union-free Designs 3:10 Karen Collins (Wesleyan University) TBA The conferences are supported by an NSF grant which allows us to provide a modest transportation allowance to those attendees who are not local. We also gratefully acknowledge support from Smith College and Wesleyan University. Our Web page site has directions to Smith College, abstracts of speakers, dates of future conferences, and other information. The address is: http://math.smith.edu/~rhaas/coneweb.html Michael Albertson (Smith College), (413) 585-3865, albertson(at-sign)math.smith.edu Karen Collins (Wesleyan University), (860) 685-2169, kcollins(at-sign)wesleyan.edu Ruth Haas (Smith College), (413) 585-3872, rhaas(at-sign)math.smith.edu  Date: Fri, 21 Nov 1997 13:57:16 -0500 (EST) From: Sara Billey <sara(at-sign)math.mit.edu> To: combinatorics(at-sign)math.mit.edu Subject: seminar today  *********Combinatorics Seminar Today at 4:15 in 2-338********** refreshments served at 3:45 Date: Friday, November 21, 1997 Speaker: Christos Athanasiadis Title: Projections of cyclic polytopes and their fiber polytopes Given any affine projection of polytopes P --> Q, Billera and Sturmfels have defined a new polytope, called the fiber polytope of the projection. Its faces correspond to certain induced polytopal subdivisions of Q, called coherent subdivisions. We consider the cyclic polytopes C(n,d), having n vertices on the d-dimensional moment curve, and the canonical projections C(n,d) --> C(n,d') between them. We show that for d'=1, the corresponding fiber polytope has combinatorial structure that is independent of the coordinates used to define C(n,d), namely that of a zonotope with n-2 generators on the (d-1)-dimensional moment curve. We show that the combinatorics of the fiber polytope may vary along with the parameters as soon as d' is at least 2 and classify all triples (n,d,d') for which the property of coherence is independent of the coordinates for any induced subdivision of C(n,d'). This is joint work with Jesu's DeLoera, Victor Reiner and Francisco Santos. Date: Wednesday, November 26, 1997 **Holiday--No seminar** Date: Friday, November 28, 1997 **Holiday--No seminar** Date: Wednesday, December 3, 1997 Speaker: Vesselin Gasharov Title: Convexity and A-Graded Algebras Date: Friday, December 5, 1997 Speaker: Dmitry Kozlov (MIT) Title:Group action on posets Date: Wednesday, December 10, 1997 Speaker: Jesus Deloera (Geometry Institute) Title: Remarks on Viro's combinatorial construction of smooth real projective hypersurfaces **This will be the last talk of the year.  Date: Wed, 26 Nov 1997 10:38:11 +0100 To: (Recipient list suppressed) From: Hotel du Curtillard <hotel(at-sign)curtillard.com>  Fini la pollution ! Le bruit ! Le b=E9ton ! L'agressivit=E9. Venez VISITER en avant premi=E8re le site de vos prochaine vacances : http://www.curtillard.com Au coeur des Alpes fran=E7aise, =E0 1000 m=E8tres d'altitude en pleine= nature, dans un environnement prot=E9g=E9 le plus grand site 13 lacs= naturel en altitude, patrimoine historique avec la d=E9couverte du sentier= des mines de fer et un patrimoine religieux avec le plus grand centre de= bouddhiste d'Europe. Finish with pollution, noise, concrete floors, aggressivity. Come and visit= your next vacation : http://www.curtillard.com In the heart of the French Alpes at an altitude of 1000 meters, in the= middle of nature, next to 13 mountain lacks, in a land with a long= historical and religious past. Discovering of the iron mines and the= biggest Buddhism center of Europe ! <center><bold><italic><bigger><bigger>Hotel du Curtillard </bigger></bigger></italic></bold><bigger>38 580 La Ferri=E8re tel : (+33)04 76 97 50 82 fax: (+33) 04 76 97 56 57 </bigger><smaller>http://www.curtillard.com=20 hotel(at-sign)curtillard.com</smaller></center>  Date: Wed, 26 Nov 1997 15:23:26 -0500 To: kcollins(at-sign)mail.wesleyan.edu From: kcollins(at-sign)wesleyan.edu (Karen L. Collins) Subject: Job advertisement from CUNY/CSI  Deborah Franzblau would like to make everyone aware of the following opportunities at CUNY. ******************************************************** College of Staten Island City University of New York (CUNY) Department of Mathematics New Tenure-track Positions The College of Staten Island (CSI) Department of Mathematics invites applications for two new tenure-track assistant professorships, to begin September, 1998. CSI, a four-year senior college of the City University of New York (CUNY), has a newly renovated campus, which is convenient to the many colleges and research centers in central New Jersey and New York City. The department, which has 22 full-time faculty members, offers B.S. degrees in mathematics, math/cs, and math/education, and graduate- level mathematics courses for secondary-school teachers. Further information about the department and CSI can be found at http://www.library.csi.cuny.edu/dept/math. We seek candidates with outstanding research potential and productive research programs, who are also excellent teachers committed to undergraduate education. A Ph.D. is required, and postdoctoral experience is desirable. One position is open to those with experience in interdisciplinary research, who will contribute to a college-wide initiative for research and education in interdisciplinary applied mathematics. The other position is open to candidates in all fields of mathematics, who have a demonstrated interest in applications. Salaries range from approximately$34K to
$52K. Qualified candidates may be nominated for appointment to the CUNY doctoral faculty. To apply, send an AMS cover sheet, a vita, a short description of current and planned research, and a short statement on teaching experience and philosophy. At least three letters of recommendation should be sent separately. Mail all materials to Faculty Search, Prof. Bruce Chandler, Chair, Dept. of Mathematics (1S-215), College of Staten Island, 2800 Victory Blvd., Staten Island, NY 10314. If you will attend the Mathematics Meetings in Baltimore this January, please let us know the dates that you will be there. To ensure full consideration, all materials must be received by January 30, 1998. CSI is an EO/AA Employer, and is committed to maintaining a diverse faculty.  Date: Sun, 30 Nov 1997 11:34:12 -0500 From: blaw(at-sign)fields.utoronto.ca (Brenda Law) To: fpart(at-sign)fields.utoronto.ca Subject: Conference Announcement  The Fields Institute Centre de recherches mathématiques First Announcement 10th International Conference on Formal Power Series and Algebraic Combinatorics Sunday, June 14 to Friday, June 19, 1998 to be held at The Fields Institute, Toronto, Canada INVITED SPEAKERS G. Benkart (USA) P. Cameron (England) P. Dehornoy (France) B. Derrida (France) P. Diaconis (USA) C. Godsil (Canada) K. Ono (USA) B. Sturmfels (USA) J.-Y. Thibon ( France) Organizing Committee N. Bergeron, Chairman (Canada) M. Delest (France) F. Sottile (Canada) W. Whiteley (Canada) Program Committee I. Goulden, Chairman (Canada) N. Bergeron (Canada) S. Billey (USA) F. Brenti (Italy) R. Cori (France) S. Dulucq (France) K. Eriksson (Sweden) O. Foda (Australia) S. Fomin (USA/Russia) I. Gessel (USA) C. Greene (USA) A. Hamel (New Zealand) D. Kim (Korea) C. Krattenthaler (Austria) D. Krob (France) M. Noy (Spain) V. Reiner (USA) C. Reutenauer (Australia) F. Sottile (Canada) T. Visentin (Canada) M. Wachs (USA) H. Yamada (Japan) G. Ziegler (Germany) TOPICS: Algebraic and bijective combinatorics and their relations with other parts of mathematics, computer science and physics. CONFERENCE PROGRAM: Invited lectures, contributed presentations, poster sessions and software demonstrations. CALL FOR PAPERS AND POSTERS: Authors are invited to submit extended abstracts of at most 12 pages before November 30, 1997. Authors should indicate their choice of presentation appropriate for their paper: lecture or poster session. To submit: The preferred method of submission is by sending one postscript file by email to fpsac98(at-sign)fields.utoronto.ca. If an author is not able to send a postscript version of the extended abstract, four copies should be mailed to the Fields Institute at the address below. Papers should begin with a summary written in the two official languages of the conference (translations will be provided if necessary). The notifications of acceptance or rejection are scheduled for the beginning of March 1998. Published Volume: The authors whose papers will have been accepted for a lecture or a poster presentation may be invited to submit a complete version of their work to a special issue of a refereed publication, devoted to the conference FPSAC '98. The deadline for submission to the special issue is September 1, 1998. SOFTWARE DEMONSTRATIONS: Demonstrations of software relevant to the topics of the conference are encouraged. People interested in giving a software demonstration should submit a short description of the software, including the hardware requirements, before January 15, 1998, by email to fsottile(at-sign)fields.utoronto.ca. PARTICIPANT SUPPORT: Limited funds are available for partial support of participants. Requests should contain a letter of recommendation and include the estimated transportation and living expenses as well as the amount of support available from other sources. All requests should be sent in duplicate by January 15, 1998 to the Fields Institute. REGISTRATION: Until April 15, 1998, the registration fee is$200 and $100 is offered for students (with verification, such as a letter from the advisor). After April 15, 1998 fees will be$300 and \$150, respectively.  The registration fee
covers all lectures and presentations, program materials,
refreshment breaks, a copy of the abstract package, and a
dinner on Thursday night. Make cheques payable
to "Fields Institute/fpsac98". To register, please
contact the Fields Institute.

email: fpsac98(at-sign)fields.utoronto.ca  	web-site: www.fields.utoronto.ca
fax: (416) 348-9385	 	        (on-line registration available)

Sponsored by Centre de recherches mathématiques, The Fields Institute for Research in Mathematical Sciences, University of Toronto, and York University

The Fields Institute, 222 College Street,
Telephone: (416) 348-9710
Fax: (416) 348-9385


Date:           Sun, 30 Nov 1997 15:11:19 -0500
To:             kcollins(at-sign)mail.wesleyan.edu
From:           kcollins(at-sign)wesleyan.edu (Karen L. Collins)


Lauren Rose would like everyone to be aware of the following
opportunity at Bard College.  Send her some e-mail at

rose(at-sign)bard.edu

*********************************************

COMPUTER SCIENCE POSITION AT BARD COLLEGE

The Division of Natural Science and Mathematics at Bard College
invites applications for a full time, tenure track position in
computer science starting in Fall 1998.

The position requires a PhD in computer science, or a PhD in mathematics
or physics and an MS in computer science.  The candidate will be a core
member of the mathematics program, and possibly other programs within the
college.  The ability to interact with mathematicians and other scientists
at Bard is essential. The position requires a strong commitment to
excellence in teaching, including supervising undergraduate senior
projects, and an ongoing program of scholarly activity.

The candidate will teach introductory programming classes for both science
and non-science majors, as well as upper level computer science and
computational math and/or science courses. Although there is no computer
science major at Bard, we envision the development of concentrations in
computational mathematics and physics, as well as courses to support these
concentrations.

Bard is a prestigious liberal arts college located in the Hudson Valley
region of New York, 2 hours north of NYC.  Applicants should submit a
letter of application, curriculum vitae, a statement of teaching and
research interests, and 3 letters of recommendation (at least one of
which addresses teaching) to: Professor Mark Halsey, c/o Office of Human
Resources, Bard College, Annandale-on-Hudson, NY 12504.  The deadline for
applications is January 1, 1998.  Bard College is an equal opportunity
employer.  Women and minority candidates are especially encouraged to
apply.


Date:           Sun, 30 Nov 1997 15:11:00 -0500
To:             kcollins(at-sign)mail.wesleyan.edu
From:           kcollins(at-sign)wesleyan.edu (Karen L. Collins)
Subject:        second announcement


           Come to the (New) Twenty-seventh one day conference on

Combinatorics and Graph Theory

Saturday, December 13, 1997

10 a.m. to 4:30 p.m.
at
Smith College
Northampton MA 01063

Schedule

10:00  James Lewis (Univ. of Rhode Island)
A Collatz Type Difference Equation

11:10  Jeffrey Hall (Univ. of New Hampshire)
Applications of Combinatorics to
Group Representation Theory

12:10  Lunch

2:00  Charles Colbourn (Univ. of Vermont)
Group Testing and Weakly Union-free Designs

3:10  Karen Collins (Wesleyan University)
Breaking Symmetries of S5 and S6

The conferences are supported by an NSF grant which allows us
to provide a modest transportation allowance to those attendees
who are not local.  We also gratefully acknowledge support from
Smith College and Wesleyan University.

Our Web page site has directions to Smith College, abstracts of
speakers, dates of future conferences, and other information.

Michael Albertson (Smith College), (413) 585-3865,
albertson(at-sign)math.smith.edu

Karen Collins (Wesleyan University), (860) 685-2169,
kcollins(at-sign)wesleyan.edu

Ruth Haas (Smith College), (413) 585-3872,
rhaas(at-sign)math.smith.edu


Date:           Wed, 3 Dec 1997 13:10:11 -0500 (EST)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date: Wednesday, December 3, 1997
Speaker: Vesselin Gasharov
Abstract:
Let A be a finite subset of N^d. An ideal is called A-graded if it has the
same Hilbert function as the toric ideal J defined by A.  What are the
A-graded ideals?  The structure of such ideals was first studied by Arnold
who related it to continued fractions.  Arnold, Korkina, Post, and Roelofs
proved that if J defines an affine monomial curve in A^3, then every A-graded
ideal is an initial ideal of the toric ideal J.  Later Sturmfels studied
A-graded ideals in the general case and related their structure to the
convexity properties of the set A.  In particular, he showed that the
monomial A-graded ideals correspond to triangulations of the convex envelope
of A. In view of Lee's theorem that A has only regular triangulations if the
codimension is 2, Sturmfels conjectured the following generalization of the
Arnold-Korkina-Post-Roelofs result: if the toric ideal J has codimension 2,
then every A-graded ideal is an initial ideal of J.  We prove this conjecture.
The proof relies on a combinatorial description of the syzygies of J.  This
is a joint work with Irena Peeva.

Date: Friday, December 5, 1997
Speaker: Dmitry Kozlov (MIT)
Title:Group action on posets

Date: Wednesday, December 10, 1997
Speaker: Jesus Deloera (Geometry Institute)
Title: Remarks on Viro's combinatorial construction of smooth real
projective hypersurfaces
**This will be the last talk of the semester**


Date:           Wed, 10 Dec 1997 14:16:16 -0500 (EST)
From:           Sara Billey <sara(at-sign)math.mit.edu>
To:             combinatorics(at-sign)math.mit.edu
Subject:        seminar today


*********Combinatorics Seminar Today at 4:15 in 2-338**********
refreshments served at 3:45

Date: Wednesday, December 10, 1997
Speaker: Jesus Deloera (Geometry Institute)
Title: Remarks on Viro's combinatorial construction of smooth real
projective hypersurfaces
Abstract:

Hilbert's 16th problem is partially concerned with the classification of
topological types of smooth real projective hypersurfaces. It is
clearly important to have available effective methods to produce
examples of new topological types. During the 1980's Oleg Viro
developed a combinatorial technique for constructing hypersurfaces
with given topology. This technique has been highly succesful and it
was used by Ilia Itenberg, in 1993, to provide counterexamples to
the ninety year old Ragsdale conjecture.

Viro's construction of real smooth hypersurfaces uses regular
(also called convex or coherent) triangulations of convex polytopes.
Nevertheless, Viro's construction can also be applied as well to arbitrary
triangulations.  Are the combinatorial hypersurfaces coming from
non-regular triangulations, still topological types of some real smooth
hypersurfaces?  In this talk we present current advances for
the solution of this question. This is joint work with Frederick Wicklin.

**This will be the last talk of the semester.**
Have a nice vacation.  We will resume on February 4th.


Date:           Fri, 12 Dec 1997 13:28:59 -0500
To:             kcollins(at-sign)mail.wesleyan.edu
From:           kcollins(at-sign)wesleyan.edu (Karen L. Collins)


              Come to the Twenty-seventh one day conference on

Combinatorics and Graph Theory

Saturday, December 13, 1997

10 a.m. to 4:30 p.m.
at
Smith College
Northampton MA 01063

Schedule

10:00  James Lewis (Univ. of Rhode Island)
A Collatz Type Difference Equation

11:10  Jeffrey Hall (Univ. of New Hampshire)
Applications of Combinatorics to
Group Representation Theory

12:10  Lunch

2:00  Charles Colbourn (Univ. of Vermont)
Group Testing and Weakly Union-free Designs

3:10  Karen Collins (Wesleyan University)
Breaking Symmetries of S5 and S6

The conferences are supported by an NSF grant which allows us
to provide a modest transportation allowance to those attendees
who are not local.  We also gratefully acknowledge support from
Smith College and Wesleyan University.

Our Web page site has directions to Smith College, abstracts of
speakers, dates of future conferences, and other information.