2 papers
math.DG2026
Virasoro extensions for diffeomorphisms with breaks
Anton Izosimov, Boris Khesin, Howard Xiao
We study homeomorphisms of the circle that are smooth diffeomorphisms away from a finite set of points. These "broken diffeomorphisms" do not form a Lie group, but instead natu…
math.DS2025
Pensive billiards, point vortices, and the silver ratio
Theodore D. Drivas, Daniil Glukhovskiy, Boris Khesin
We define a new class of plane billiards - the `pensive billiard' - in which the billiard ball travels along the boundary for some distance depending on the incidence angle before…