Semi-normal spaces and some functions

On R-Closed Maps and R-Homeomorphisms in Topological Spaces

“…g-closed [18], pre-closed [10], gp-closed [10], gpr-closed [19], gsp-closed, α-closed, αg-closed) if f(V) is closed (resp. g-closed, pre-closed, gp-closed, gpr-closed, gsp-closed, α-closed, αg-closed) in (Y,σ) for every closed set V in (X,τ).…”

On a generalization of normal, almost normal and mildly normal spaces II

“…A subset A of a space X is called generalized preregular closed [8] or regular generalized preclosed [14]…”

“…In 1970, the first step of generalizing closed sets was done by Levine [9]. After that time, many authors have introduced and studied the relationships between separation axioms and generalized closed sets [13,14]. The notions of generalized closed sets have been investigated extensively by many authors because the notion of generalized closed sets is a natural generalization of closed sets.…”

On πgs-closed sets in topological spaces

“…This notion was further studied by Noiri [18]. On the other hand, Zaitsav [22] introduced the concepts of π-closed sets and a class of topological spaces called quasi normal spaces.…”