Alpha representation and spectral properties of multiparton functions

By means of parametric representation for Feynman integrals it is shown that the functions $F(x_1,\ldots,x_k)$ and $\varphi(x_1,\ldots,x_k)$, whose generalized moments are proportional to the reduced matrix elements of the k-particle composite operators, possess the spectral properties needed for their parton interpretation.