Smooth structures and nearby Lagrangians
A basic question in symplectic topology is to classify the Lagrangian submanifolds of a given symplectic manifold. I'll discuss some results concerning smooth structures on Lagrangians, and how to detect them using Floer theory. Based on joint work with Ivan Smith.
Framed Morse functions
Morse & Cerf functions
Galatius-Madsen-Tilmann-Weiss & invertible TQFTs
Classifying spaces of diffeomorphism groups
Embedded submanifolds & scanning
The $h$-principle
The one-dimensional case
Dualisability
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Complete Segal spaces and $(\infty, n)$-categories
Topological Fukaya category for surfaces
This talk presents a purely topological model for wrapped Fukaya categories of surfaces, avoiding symplectic geometry and analytical techniques. The construction is based on combinatorial data of arcs and trajectories on surfaces, yielding a triangulated category that models the wrapped Fukaya category in a topological way. As an application, we obtain a homological mirror symmetry correspondence with gentle algebras arising from the same surface data.
Wrapped Fukaya category for surfaces
This talk focuses on the Fukaya category of surfaces, offering a more concrete and combinatorial perspective on these objects from symplectic geometry. For surfaces, the category can be described in terms of curves and their intersections, making key ideas more accessible. We outline this construction and explain its role in mirror symmetry, where it connects to algebraic structures on the mirror side.
Hopfological algebra, revisited
This talk is based on joint work with Omar Gómez (Bielefeld) and Marius Nielsen (NTNU). Hopfological algebra is a variant of classical homological algebra introduced by Khovanov and Qi, motivated by potential applications in the categorification of quantum invariants of 3-manifolds. In this talk, I will explain an infinity-categorical approach to the theory that leads, in particular, to refined foundations as well as to "hopfological analogues" of classical invariants such as Hochschild (co)homology.
Orthogonality as Graph with an Application to Finite Coxeter Groups
The common neighborhood of a set of nodes in a simple graph is a
Galois connection with associated closure operation on the power set
of the node set. An application of this concept to root systems
yields a new Galois connection on the (conjugacy classes of) parabolic
subgroups of a finite Coxeter group which we have used to refine
Howlett's description of the normalizers of its parabolic subgroups.
This talk is based on joint work G. Roehrle and J.M. Douglass
(arXiv:2509.15850).
Seminar Cobordism Hypotheses
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Syntomification of rigid-analytic varieties over $\mathbb{Q}_p$
I will describe a stacky approach to syntomic cohomology of rigid spaces over $\mathbb{Q}_p$, which is an analytic analogue of the syntomification of a $p$-adic formal scheme of Drinfeld and Bhatt--Lurie. This yields a notion of syntomic cohomology of rigid spaces with coefficients which satisfies Poincaré duality, affords a theory of Chern classes and compares both to Hyodo--Kato and proétale cohomology.
In the first part of the talk, I will explain what syntomic cohomology is, why one should care about a stacky approach and what the syntomification looks like geometrically. In the second part, I will show how one can use this geometric point of view to obtain cohomological comparison theorems.
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