On Inverse Limit Of Function Spaces
In this note we study the relation between -spaces and -spaces and prove that a -space with a -hereditarily closure-preserving -network consisting of compact subsets is a -space, and that a -space with a point-countable -network consisting of compact subsets need not be a -space.
Si studiano le condizioni sotto cui l’immagine (o l'immagine inversa) di uno spazio localmente -chiuso sia localmente -chiuso.
We give a straightforward topological description of a class of spaces that are separable, countably compact, countably tight and Urysohn, but not compact or sequential. We then show that this is the same class of spaces constructed by Manes [Monads in topology, Topology Appl. 157 (2010), 961--989] using a category-theoretical framework.
We call a function P-preserving if, for every subspace with property P, its image also has property P. Of course, all continuous maps are both compactness- and connectedness-preserving and the natural question about when the converse of this holds, i.e. under what conditions such a map is continuous, has a long history. Our main result is that any nontrivial product function, i.e. one having at least two nonconstant factors, that has connected domain, range, and is connectedness-preserving...
We prove the existence of -matrix points among uniform and regular points of Čech–Stone compactification of uncountable discrete spaces and discuss some properties of these points.