3 papers
math.GT2026
The Casson-Sullivan invariant for homeomorphisms of 4-manifolds
Daniel A. P. Galvin
We investigate the realisability of the Casson-Sullivan invariant for homeomorphisms of smooth -manifolds, which is the obstruction to a homeomorphism being stably pseudo-isotop…
math.GT2025
Pseudo-isotopy versus isotopy for homeomorphisms of 4-manifolds
Daniel Galvin, Isacco Nonino
We define obstructions which obstruct topological pseudo-isotopies from being isotopic to isotopies in dimension four. These match the smooth obstructions of Hatcher-Wagoner for sm…
math.GT2025
Non-smoothable homeomorphisms of -manifolds with boundary
Daniel Galvin, Roberto Ladu
We construct the first examples of non-smoothable self-homeomorphisms of smooth -manifolds with boundary that fix the boundary and act trivially on homology. As a corollary, we…