David Trotman

Friday, December 6th,2019.  Room   4-001  , at 4:00 p.m



Title: Some geometric properties of Whitney stratified sets


Abstract: In 1965 Whitney introduced conditions (a) and (b) on a stratification
of an analytic variety, ensuring stability of transversality to strata and constance
of the local topological type near a stratum. We discuss geometric properties
of smooth Whitney stratified sets and possible improvements, in particular to
the local bilipschitz type of definable sets in o-minimal structures. We describe
recent refinements of the Thom-Mather isotopy theorem, and an application to
Whitney cellulation of Whitney stratified sets which implies the proof of a 1981
homology conjecture of Goresky.