When I integrate the product of two DiracDelta functions, I get a single DiracDelta, i.e., Integrate[DiracDelta[x-y] DiracDelta[x-z],{x,-Infinity,Infinity}] = DiracDelta[y-z] as expected. However, sometimes the integral of a product of DiracDelta functions does not give the correct result. For instance one would expect: Integrate[DiracDelta[u+z(1-x)] DiracDelta[v-z y], {z,-Infinity,Infinity}] = DiracDelta[v(1-x)+u y] but instead gets a convergence error:Read more