Introduzione


Abstract


En
Given a topological space (S,\tau) and a subset X of S, the topology \tau(x) = ≤ft{A \cup (A' ∩ X)/A,A' ∈ τ \right} is called the simple extension of \tau by X (see Levine 3).Here we show how to recognize when two subsets X and Y of S define the same simple extension of \tau and we give a characterization of those expansions of \tau which are simple extensions of \tau by suitable subsets of S.

DOI Code: §

Full Text: PDF


Creative Commons License
This work is licensed under a Creative Commons Attribuzione - Non commerciale - Non opere derivate 3.0 Italia License.