Factorization theorems for extensions of maps
Factorizations of normality via generalizations of -normality
The notion of -normality was introduced and studied by Arhangel’skii, Ludwig in 2001. Recently, almost -normal spaces, which is a simultaneous generalization of -normal and almost normal spaces, were introduced by Das, Bhat and Tartir. We introduce a new generalization of normality, namely weak -normality, in terms of -closed sets, which turns out to be a simultaneous generalization of -normality and -normality. A space is said to be weakly -normal (w-normal if for every pair of disjoint...
Finite dimensions defined by means of -coverings
First order topology [Book]
Forcing tightness in products of fans
We prove two theorems that characterize tightness in certain products of fans in terms of families of integer-valued functions. We also define several notions of forcing that allow us to manipulate the structure of the set of functions from some cardinal θ to ω, and hence, the tightness of these products. These results give new constructions of first countable <θ-cwH spaces that are not ≤θ-cwH.