分野別セミナー

After a short review of expansivity properties of algebraic dynamical systems and existence of homoclinic points in general, I will discuss a specific case of principal algebraic actions of the discrete Heisenberg group. Criterium for expansivity based on Allan's local principle will be presented, as well as the novel link via representation theory to time-frequency analysis and difference equations with almost periodic coefficients. This is joint work with M. Göll and K. Schmidt.