Scattering Amplitudes, Multi-variate Residues and Valuated Matroids

Multi-variate residues on Grassmannians G(k,n) and moduli spaces M0,n are ubiquitous in the study of scattering amplitudes; they provide a powerful and essential tool. Amenable theories include the biadjoint scalar, NLSM, Yang-Mills, gravity and N=4 Super Yang-Mills and more. I will review a relation between such multi-variate residues and the real tropical Grassmannian, i.e. the set of valuated matroids which are realizable over the real numbers. In this way, a physical problem becomes a question in geometric combinatorics.