Topics in Diophantine Approximation

18.784: Seminar in Number Theory, Spring 2026

Welcome to 18.784: Seminar in Number Theory! This course is a Communication Intensive in Mathematics (CI-M) for undergraduates at MIT.

This semester, we will explore Diophantine approximation — an area of mathematics that studies how close rational numbers can be to irrational numbers. The subject has very classical origins in number theory and has intersections with a breadth of mathematical disciplines including:

  • Algebraic geometry
  • Algebraic number theory
  • Analytic number theory
  • Complex analysis
  • p-adic analysis
  • Dynamical systems
  • Game theory

Prerequisites for the course:

Additional mathematical background in any of the following will be helpful but not required:

Students will learn how to communicate specific topics in Diophantine approximation through blackboard talks, a short expository term paper, and peer review.

Course files (to be updated during the semester):


Google forms:

The class meets in Room 2-151 from 2:30pm—4:00pm (ET) on Tuesdays and Thursdays.
Robin's office hours are in 2-238 from 3:00pm—4:00pm (ET) on Wednesdays.

To contact Robin, please send an email or a message in the course Slack.
The WRAP (communications) instructor, Emily Robinson, can be reached at erobin73@mit.edu.


Course schedule (subject to change)

Date Speaker Title References
February 3
(Background questionnaire due 2:30pm on February 4)
Robin Zhang Organizational meeting

Emily Robinson

Communications workshop: preparing for presentations

[Ruf19]

Robin Zhang

What is Diophantine approximation

[Bak75]§1
[Bur00]§1
[Sch80]§1
February 5 All students 3-minute introductory talks (favorite definition / example / theorem)
February 10 Ana Illanes Martinez De La Vega & Alicia Lin What is a real number [HW71]§4.1-4.3
[Rud76]§1
[Sch14]§1.1-1.3
[Sut15]§1.1-1.3

Cheuk Hei Chu & Paul Gutkovich

What is a Farey sequence

[Dum22]§6.2.1
[HW71]§3.1-3.8

Reina Wang & Tony Wu

What is modular arithmetic

[HW71]§5.2-5.5, 6.1
[IR90]§3-4, 7
[Ros11]§4-5, 9
[Smi23]§II
February 12 Fiona Lee & Julianna Lian What is the pigeonhole principle [Bic20]
[Goe15]

Diego Andrés Rivera Orona & Alex Yang

What is the Euclidean algorithm

[Ros11]§3.4

Yina Wang & Zachary West

What is equidistribution

[KN74]§1.1
February 17 President's Day Tuesday (no meeting) President's Day Tuesday (no meeting)
February 19 Benjamin Li & Adelmo Morrison Orozco What is an algebraic integer [Mur15]
[Ogg10]§1

Tiago Oliveira Marques & Ghaura Mahabaduge

What is a p-adic number

[Con06]
[Gou97]§1-3

Emily Robinson

Communications workshop: effective mathematics presentations

[Ben01]§1
February 24 — (pair)

— (pair)



— (pair)


February 26 — (pair)

— (pair)



— (pair)


March 3 — (pair)

— (pair)



— (pair)


March 5

Emily Robinson

Communications reading workshop: finding sources for research papers

March 10






March 12

Emily Robinson

Communications reading workshop: genre sources for research papers

March 17






March 19
(Paper topic proposal due 2:30pm)






March 24 Spring Break (no meeting) Spring Break (no meeting)
March 26 Spring Break (no meeting) Spring Break (no meeting)
March 31






April 2






April 7



April 9
(Paper first draft due 2:30pm)

Emily Robinson

Communications writing workshop: guiding text

April 14



April 16

Emily Robinson

Communications writing workshop: writing economy

April 21



April 23
(Paper second draft due 2:30pm)



April 28



April 30
(Peer review reports due 2:30pm)
All students Peer review on papers
May 5



May 7



May 12
(Paper final draft due 2:30pm)
All students Course retrospective & celebration

Books

Notes

Communications resources