Baire 1 Functions and the Topology of Uniform Convergence on Compacta

Abstract

Let X be a Tychonoff topological space, B1(X,R) be the space of real-valued Baire 1 functions on X and τUC be the topology of uniform convergence on compacta. The main purpose of this paper is to study cardinal invariants of (B1(X,R),τUC). We prove that the following conditions are equivalent: (1) (B1(X,R),τUC) is metrizable; (2) (B1(X,R),τUC) is completely metrizable; (3) (B1(X,R),τUC) is Čech-complete; and (4) X is hemicompact. It is also proven that if X is a separable metric space with a non isolated point, then the topology of uniform convergence on compacta on B1(X,R) is seen to behave like a metric topology in the sense that the weight, netweight, density, Lindelof number and cellularity are all equal for this topology and they are equal to c= |B1(X,R)|. We find further conditions on X under which these cardinal invariants coincide on B1(X,R).