The Simplicity Conjecture

The Simplicity Conjecture

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Daniel Cristofaro-Gardiner, IAS

Zoom link:

https://princeton.zoom.us/j/745635914  

 

I will explain recent joint work proving that the group of compactly supported area preserving homeomorphisms of the two-disc is not a simple group; this answers the ”Simplicity Conjecture” in the affirmative. Our proof uses new spectral invariants, defined via periodic Floer homology, that I will introduce: these recover the Calabi invariant of monotone twists.