Superharmonic Functions in Brelot Spaces Mohammad Alakhrass

We study superharmonic functions, reduced function, harmonic measures and Jensen measures in Brelot spaces. We introduce the concept of quasi multiply superharmonic functions on a product of Brelot spaces and study their properties. A main result obtained is characterizing the quasi superharmonic functions in terms of harmonic, finely harmonic and Jensen measures. Then we prove that a quasi multiply superharmonic function on a product of Brelot spaces equals its lower semicontinuous regularization out side of a 2-negligible set. Further we give a sufficient condition on a Brelot space under which it becomes an extension space for superharmonic functions. As a result we characterize the extreme Jensen measures in such spaces. Finally we study extreme Jensen measures relative to several classes of multiply superharmonic functions. Это и многое другое вы найдете в книге Superharmonic Functions in Brelot Spaces (Mohammad Alakhrass)