A VANISHING RESULT FOR TORIC VARIETIES ASSOCIATED WITH ROOT SYSTEMS

Abstract

Consider a root system $R$ and the corresponding toric variety $V_R$ whose fan is the Weyl fan and whose lattice of characters is given by the root lattice for $R$. We prove the vanishing of the higher cohomology groups for certain line bundles on $V_R$ by proving a purely combinatorial result for root systems. These results are related to a converse to Mazur’s Inequality for (simply-connected) split reductive groups.