The Gerstenhaber product $\HH^2(A)\times \HH^2(A)\to \HH^3(A)$ of affine toric varieties

Abstract

For an affine toric variety $\spec(A)$, we give a convex geometric interpretation of the Gerstenhaber product $\HH^2(A)\times \HH^2(A)\to \HH^3(A)$ between the Hochschild cohomology groups. In the case of Gorenstein toric surfaces we prove that the Gerstenhaber product is the zero map. As an application in commutative deformation theory we find the equations of the versal base space (in special lattice degrees) up to second order for not necessarily isolated toric Gorenstein singularities. Our construction reproves and generalizes results obtained in [1] and [13].