Kolmogorov decomposition of conditionally completely positive definite kernels (Q830188)

The authors study conditionally completely positive definite kernels taking values in the algebra of bounded self-maps of a \(C^*\)-algebra. The main result is the Kolmogorov decomposition for conditionally completely positive definite kernels satisfying certain algebraic properties. The authors also present a characterization of conditionally completely positive definite kernels majorized by a kernel under some mild conditions, and find a sufficient condition for the existence of an extreme point of a convex set consisting of some special kernels.