Marcelo Aguiar: Algebra based on real hyperplane arrangements


Abstract

We discuss an algebraic theory based on the geometry of real hyperplane arrangements. We focus on the notion of Hopf monoid, for which the key ingredient is furnished by the projection maps of Tits. Geometric structures associated to arrangements afford examples of Hopf monoids. We discuss examples arising from chambers, subarrangements, and deformations of zonotopes. When specialized to the braid arrangement, we recover Hopf algebraic structures on combinatorial objects such as graphs, linear orders, and generalized permutahedra studied in previous work with Federico Ardila. This is joint work in progress with Swapneel Mahajan.