David Ralston
Title: Generic ergodicity of periodic billiards

Abstract: In joint work with S. Troubetzkoy (Luminy), we show that for a a certain category of compact square-tiled surfaces, periodic group extensions formed by a randomized process have the property that geodesic flow is ergodic in almost every direction. The same techniques may also show that certain specific constructions which we refer to as staircases have the same property.