Mixing for measure-preserving group actions is a fundamental notion in ergodic theory, with different phenomena arising for different acting groups. In 1993, Klaus Schmidt and Tom Ward proved that 2-mixing implies mixing of all orders for actions by commuting automorphisms of connected groups. Tom Ward explains how he became interested in this problem, and describes how a chance encounter with a paper on a seemingly unrelated problem in number theory played a key role.
Categories: math.DS math.NT