Bob Lutz: Electrical networks and hyperplane arrangements

Abstract

This talk defines Dirichlet arrangements, a generalization of graphic hyperplane arrangements arising from electrical networks and order polytopes of finite posets. After establishing some basic properties we characterize Dirichlet arrangements whose Orlik-Solomon algebras are Koszul and show that the underlying matroids satisfy the half-plane property. We also discuss the role of Dirichlet arrangements and harmonic functions on electrical networks in problems coming from mathematical physics.