Random Linear Extensions of Grids

A grid poset – or grid for short – is a product of chains. We ask, what does a random linear extension of a grid look like? In particular, we show that the average “jump number,” i.e., the number of times that two consecutive elements in a linear extension are incomparable in the poset, is close to its maximum possible value. The techniques employed rely on entropy arguments. We finish with several interesting questions about this wide-open area.