## Topology Seminar: Progress ( or lack thereof ) on the 4D topological surgery conjecture

Seminar | January 13 | 2:10-3 p.m. | 740 Evans Hall

Mike Freedman, UCSB

Department of Mathematics

Recent joint work with Slava Krushkal yields a new class of universal surgery problems which are “1/2 $\pi_1$ null”. Superficially this seems like 1/2 the way from where we were stuck for 25 years and the goal of proving a surgery theorem with no fundamental group restriction. But there is a reason to be skeptical that we are even headed in the right direction. I’ll end by explaining my suspicion that this “progress” is a mirage.

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