Tukey reduction among analytic directed orders

Abstract

This is a survey of recent work on the structure of Tukey reductions among analytic σ-ideals of compact subsets of compact metric spaces and analytic P-ideals of sets of natural numbers. An attempt is made to organize the results into a unified whole. This organization makes it possible to identify natural unresolved problems. Some new joint results with Stevo Todorcevic are announced.