One of the earliest fundamental applications of Lagrangian Floer
theory is detecting the non-displaceablity of a Lagrangian
submanifold. Many progress and generalisations have been made since
then but little is known when the Lagrangian submanifold...
This is the second in a series of talks on "two realizations."
We discuss equivariantization and de-equivariantization for a
group GG, which relate categories with GG-actions and
categories with RepG-actions, and how this relates to the notion
of...
We show that the direct product of an infinite, finitely
generated Kazhdan Property (T) group and a finitely presented, not
residually finite amenable group admits no sofic approximation by
expander graphs. Joint work with Andreas Thom.
Expander graphs are graphs which simultaneously are both sparse
and highly connected. The theory of expander graphs received a
lot of attention in the past half a century, from both computer
science and mathematics. In recent years, a new theory of...
A 1948 theorem of de Bruijn and Erdős says that
if nn points in a projective plane do not lie all on a
line, then they determine at least n lines. More generally, Dowling
and Wilson conjectured in 1974 that for any finite set of vectors
spanning a...
Non-constructive existence proofs, which establish the existence
of objects without furnishing an efficient algorithm to produce
examples, abound in mathematics. How hard is it, computationally,
to find objects whose existence is guaranteed non...
The purpose of this talk is to explore how Lagrangian Floer
homology groups change under (non-Hamiltonian) symplectic isotopies
on a (negatively) monotone symplectic
manifold (M,ω)(M,ω) satisfying a strong non-degeneracy
condition. More precisely...
