English

Compactness in function spaces

General Topology 2018-03-29 v1

Abstract

Let XX be a locally compact topological space, (Y,d)(Y,d) be a boundedly compact metric space and LB(X,Y)LB(X,Y) be the space of all locally bounded functions from XX to YY. We characterize compact sets in LB(X,Y)LB(X,Y) equipped with the topology of uniform convergence on compacta. From our results we obtain the following interesting facts for XX compact: \bullet If (fn)n(f_n)_n is a sequence of uniformly bounded finitely equicontinuous functions of Baire class α\alpha from XX to R\Bbb R, then there is a uniformly convergent subsequence (fnk)k(f_{n_k})_k; \bullet If (fn)n(f_n)_n is a sequence of uniformly bounded finitely equicontinuous lower (upper) semicontinuous functions from XX to R\Bbb R, then there is a uniformly convergent subsequence (fnk)k(f_{n_k})_k; \bullet If (fn)n(f_n)_n is a sequence of uniformly bounded finitely equicontinuous quasicontinuous functions from XX to YY, then there is a uniformly convergent subsequence (fnk)k(f_{n_k})_k.

Keywords

Cite

@article{arxiv.1803.10493,
  title  = {Compactness in function spaces},
  author = {Ľubica Holá and Dušan Holý},
  journal= {arXiv preprint arXiv:1803.10493},
  year   = {2018}
}