The MIT Geometry and Topology Seminar is scheduled for Mondays at 3PM (Eastern US time) and will be held over Zoom. The link for the seminar can be found here. The password is "".

**September 14 (Duncan McCoy):** Double slicing for links

Abstract: A knot in *S*^{3} is said to be *doubly slice* if it arises as the intersection of an unknotted 2-sphere in *S*^{4} with the equatorial *S*^{3}. There are several ways this definition can be generalized to links. I will discuss these competing definitions and give some interesting examples. This is joint work with Clayton McDonald.

**September 21 (Yi Ni):** Seifert fibered surgeries on hyperbolic fibered knots

Let *K* be a hyperbolic fibered knot such that *p/q*-surgery on *K* is either reducible or an atoroidal Seifert fibered space. We prove that if the monodromy of *K* is right-veering, then
0*≤ p/q ≤* 4*g(K)*. The upper bound 4*g(K)* cannot be attained if *K* is an L-space knot. As a consequence, we get new results on the characterizing slopes of torus knots.

**September 28 (Mark Powell):** Stable diffeomorphism of 4-manifolds

Abstract: I will survey the relationships between some popular equivalence relations on 4-manifolds, before focussing on the classification of 4-manifolds up to stable diffeomorphism, meaning up to connected sum with copies of *S*^{2} x *S*^{2}.

**October 5 (Ian Zemke):** TBA

** October 19 (Patrick Orson):** TBA