Abstract:

It is proved that Tych, the category of complete regular pretopological spaces and continuous mappings between them, and PTopi (i=0,1,2,3) are epireflective subcategories of PTop, which is the category of pretopological spaces and continuous mappings between them.

Key words: pretopological space, separation axiom, monomorphism, epimorphism, extremal monomorphism, epireflective subcategory