Modules and extremal completely positive maps (Q743467)

The author determines the extreme points of the convex set of positive definite kernels and characterizes extremal autocorrelation functions of stochastic processes. He also gives necessary conditions for open half lines to be extremal rays of the convex set of positive definite kernels and presents a generalization for the Choi isomorphism. A complete characterization of the extreme points of the convex set of CP maps in the context of modules is given. He defines CP sesquilinear form valued `instruments' and determines their extreme points.