6533b857fe1ef96bd12b3919

RESEARCH PRODUCT

On the structure of positive homomorphisms on algebras of real-valued continuous functions

Jose L. Blasco

subject

Discrete mathematicsMathematics::LogicAlgebra homomorphismKernel (algebra)Isomorphism theoremRing homomorphismGeneral MathematicsAlgebra representationMathematics::General TopologyWeightHomomorphismCoimageMathematics

description

In this paper we study the structure of positive homomorphisms on real function algebras. We prove that every positive homomorphism is completely characterized by a family of sets and when the algebra is inverse-closed, by an ultrafilter of zero-sets of functions of the algebra. We show that the known sufficient conditions for every homomorphism of a real function algebra to be countably evaluating or a point evaluation are not necessary. Our results enable us to characterize the countably evaluating algebras as well as the Lindelof spaces as the spaces in which for every algebra, each countably evaluating homomorphism is a point evaluation.

https://doi.org/10.1023/b:amhu.0000023212.91183.38