The ACO Seminar (2012-2013)

Convex sets are combinatorially complicated because convexity is defined via addition and multiplication. Stairconvex sets are siblings of convex sets, whose definition involves no arithmetic, and that form a geometry of their own. I shall describe the solutions to several problems in classic combinatorial convexity that use stairconvex sets, and will mention the still-mysterious connections with algebraic topology and logic.