Polytope Algebra and Tropical Cycles

Research Horizons Seminar
Wednesday, December 7, 2011 - 12:05
1 hour (actually 50 minutes)
Skiles 005.
Georgia Tech
A polytope is a convex hull of a finite set of points in a vector space.  The set of polytopes in a fixed vector space generate an algebra where addition is formal and multiplication is the Minkowski sum, modulo some relations.  The algebra of polytopes were used to solve some variations of Hilbert's third problem about subdivision of polytopes and to give a combinatorial proof of Stanley's g-Theorem that characterizes face numbers of simplicial polytopes.  In this talk, we will introduce McMullen's version of polytope algebra and show that it is isomorphic to the algebra of tropical cycles which are balanced weighted polyhedral fans.  The tropical cycles can be used to do explicit computations and examples in polytope algebra.