Geometric maximizers of Schatten norms of some convolution type integral operators

In this paper we prove that the ball is a maximizer of the Schatten p-norm of some convolution type integral operators with non-increasing kernels among all domains of a given measure in Rd. We also show that the equilateral triangle has the largest Schatten p-norm among all triangles of a given area. Some physical motivations for our results are also presented.