3-Manifold Seminar: Kronheimer-Mrowka invariants of bifolds

Event details Date: Tuesday, September 8, 2026 Time: 9:40 AM to 11:00 AM Location: 939 Evans Hall Type: Lecture / Workshop About this event Speaker: Ian Agol, UC Berkeley We will begin discussing the papers of Kronheimer-Mrowka on invariants of bifolds defined using instanton Floer homology. They define an invariant $J^#$ of webs and foams which are the singular loci of bifolds in 3- and 4-dimensions. When the web $W$ is planar in $S^3$, they conjecture that the dimension of $J^#(W)$ is the number of Tait colorings of $W$, which, if true, would imply a new proof of the 4-color theorem. Official event details: https://events.berkeley.edu/math/event/329480-3-manifold-seminar-kronheimer-mrowka-invariants-of