Analys- och sannolikhetsseminarium

Abstrakt finns enbart på engelska: In this talk we consider linear functionals on an unital commutative R-algebra. Recently has been obtained a characterization for moment functionals, on compact sets of characters, depending only on the given functionals. In this talk, we establish alternative characterizations. For example, we obtain a characterization of a moment functional on a product of symmetric intervals in which we do not assume that the functional is positive semidefinite but positive on an Archimedean semiring, and a characterization of a moment functional for which the compact support of the representing measure is a subset of the support of the representing measure in the characterization mentioned at the beginning of the abstract. We also give some applications of these characterizations. At the end of the talk we consider an unital commutative semigroup S, with involution, and characterize moment functions on compact sets of characters of S.