The Michigan Topology Intercity Symposium (MITIS) is an annual meeting of topologists in Michigan.
The 2026 symposium will be held on Saturday, April 25, 2026 at Michigan State University in East Lansing, MI.
Speakers:
John Baldwin (Boston College)
Zhenyi Chen (Michigan State University)
Aliakbar Daemi (Washington University in St. Louis)
Jake Rasmussen (University of Illinois Urbana-Champaign)
Roberta Shapiro (University of Michigan)
Organizers: Jesse Cohen, Matt Hedden, Matt Stoffregen, Linh Truong, and Hugo Zhou
Registration: If you would like to attend, please register here.
Location: Talks will be held in Wells Hall, C-Wing, Room C304. Parking is available in Lots 39 and 79.
Schedule:
9:30-10am Refreshments
10:00-10:50am John Baldwin
11:10-12:00pm Roberta Shapiro
12:00-1:30pm Lunch Break
1:30-2:20pm Zhenyi Chen
2:40-3:30pm Aliakbar Daemi
3:30-4pm Refreshments
4:00-4:50pm Jake Rasmussen
John Baldwin
Title: Ribbon concordance and fibered predecessors
Abstract: Agol recently proved Gordon’s conjecture that ribbon concordance defines a partial order on knots in the 3-sphere. Gordon further conjectured that this partial order is well-founded, meaning that there is no infinite descending sequence of knots under ribbon concordance. We pose an even more basic conjecture: for every knot K there are only finitely many knots which are ribbon concordant to K. Our main result is that for each K there are only finitely many fibered knots ribbon concordant to K. Our proof uses results about maps on Floer homology induced by ribbon Z/2-homology cobordisms, a relationship between the Floer homology of a fibered knot and the fixed points of its monodromy, and a new satellite inequality in knot Floer homology proven using the immersed curves approach to bordered Floer homology. This is joint work with Jonathan Hanselman and Steven Sivek.
Zhenyi Chen
Title: Sheaf Quantization in Plumbings
Abstract: In this talk, I will present a local-to-global formula for Lagrangian Floer homology in plumbings of cotangent bundles. To demonstrate the formula, I will show you detailed computations in once punctured surfaces, via quiver representations. The content of this talk is part of an ongoing attempt, joint with Dogancan Karabas, to give a sheaf-theoretic description of Heegaard Floer homology.
Aliakbar Daemi
Title: Mapping class group actions on character varieties for punctured surfaces
Abstract: Character varieties of Riemann surfaces provide an important class of symplectic manifolds. For example, given a punctured Riemann surface S, one can consider the space of all conjugacy classes of SU(2)-representations of the fundamental group of S such that the image of each small loop around a puncture lies in the conjugacy class of traceless elements in SU(2). One may also consider a variation in which some of these loops are instead mapped to a central element of SU(2). These charcater varieties are (possibly singular) symplectic manifolds. In the case that the character variety is smooth, taking pullback of the elements of the character variety with respect to any fixed non-trivial element of the mapping class of S determines a symplectomorphism. In this talk, I will discuss a result showing that, for all but finitely many choices of S, any such symplectomorphism is not isotopic to the identity through symplectomorphisms. I will also discuss implications of our techniques for the set of Lagrangian spheres up to Hamiltonian isotopy in some of these character varieties. This is based on joint work with Chris Scaduto.
Jake Rasmussen
Title: Operators and Correspondences in Heegaard Floer homology
Abstract: The bordered Floer homology of a 3-manifold with torus boundary can be interpreted as a collection of immersed curves in the punctured torus. Similarly, the bordered Floer homology of a 3-dimensional cobordism M:T^2->T^2 give an operator F_M which eats an immersed curve on the punctured torus and spits out another such curve. (More formally, F_M is a functor from the Fukaya category of the punctured torus to itself.) I'll describe a class of examples in which these operators are given by explicit geometric correspondences. Based on joint work with Holt Bodish and James Pascaleff.
Roberta Shapiro
Title: Geometry, topology, and combinatorics of fine curve graphs
Abstract: The fine curve graph of a surface is a graph that encodes information about curves on a surface and their interaction. This is similar to the more classical curve graph, which encodes information about the isotopy classes of curves on a surface. In this talk, we construct both graphs and compare and contrast some properties, such as the groups that act on them, their geometry, their topology, and their combinatorics. Some shared results will be work joint with Ryan Dickmann, Zachary Himes, and Alex Nolte.
Abstract: We consider satellite operations where the corresponding 2-component link is an L-space link. This family includes many commonly studied satellite operators, including cables, the Whitehead operator, and a family of Mazur operators. Using a bordered module reinterpretation of the link surgery formula by Zemke, we give a formula to compute the knot Floer complex of a satellite of K under L-space satellite operators, in terms of the knot complex of K. This is joint work with Daren Chen and Ian Zemke.