A quasitopos containing CONV and MET as full subcategories

[摘要] We show that convergence spaces with continuous maps and metric spaces withcontractions, can be viewed as entities of the same kind. Both can be characterized by a “limit function”λwhich with each filterℱassociates a mapλℱfrom the underlying set to the extended positive real line. Continuous maps and contractions can both be characterized as limit function preserving maps.The properties common to both the convergence and metric case serve as a basis forthe definition of the category, CAP. We show that CAP is a quasitopos and that, apart from the categories CONV, of convergence spaces, and MET, of metric spaces, it also contains the category AP of approach spaces as nicely embedded subcategories.

[学科分类] 数学（综合）