Epimorphisms in categories of separated fuzzy topological spaces (Q1313031)

Considering Salbany-type closure operator [\textit{S. Salbany}, Categor. Topol., Proc. Conf. Mannheim 1975; Lect. Notes Math. 540, 548-565 (1976; Zbl 0335.54003)], the authors characterize the epimorphisms in three full subcategories of \(FTS\) (= the category of fuzzy topological spaces and continuous mappings) namely, \(FTS_ 0\) of \(0^*\)-\(T_ 0\)-spaces of \textit{P. Wuyts} and \textit{R. Lowen} [Fuzzy Sets Syst. 19, 51-80 (1986; Zbl 0606.54004)], \(FTS_ 1(=FT_ S)\) of \(T_ 1\)-spaces of \textit{M. H. Ghanim}, \textit{E. E. Kerre} and \textit{A. S. Mashhour} [J. Math. Anal. Appl. 102, 189-202 (1984; Zbl 0543.54006)] and \(FTS_{\alpha_ 2}\) of \(\alpha\)-\(T_ 2\)-spaces of \textit{S. E. Rodabaugh} [Topology Appl. 11, 319-334 (1980; Zbl 0484.54008)]. In dealing with the subcategory \(FTS_ 0\), the authors construct a nice result under Proposition 2.4. Some examples in relation to the work of previous authors are also mentioned in this interesting article.