-spaces and -sets
Semi separation axioms and hyperspaces.
Semi-generalized continuous maps in topological spaces.
Semi-precontinuous functions and properties of generalized semi-preclosed sets in topological spaces.
Semiregular frames
Separatedness in constructive topology.
Separation axioms for partially ordered convergence spaces.
Separation properties and n-point topological extensions
Separation properties of the Wallman ordered compactification.
Sequences of disjoint open sets
Sequential compactness vs. countable compactness
The general question of when a countably compact topological space is sequentially compact, or has a nontrivial convergent sequence, is studied from the viewpoint of basic cardinal invariants and small uncountable cardinals. It is shown that the small uncountable cardinal 𝔥 is both the least cardinality and the least net weight of a countably compact space that is not sequentially compact, and that it is also the least hereditary Lindelöf degree in most published models. Similar results, some definitive,...
Skeletally Dugundji spaces
We introduce and investigate the class of skeletally Dugundji spaces as a skeletal analogue of Dugundji space. Our main result states that the following conditions are equivalent for a given space X: (i) X is skeletally Dugundji; (ii) every compactification of X is co-absolute to a Dugundji space; (iii) every C*-embedding of the absolute p(X) in another space is strongly π-regular; (iv) X has a multiplicative lattice in the sense of Shchepin [Shchepin E.V., Topology of limit spaces with uncountable...
Sober spaces and continuations.
Sobre el retículo de proximidades de Lodato.
Sobrification of partially ordered sets.
Some further aspects of G. Preuss' theory of E-connected spaces
Some generalisations of spaces
Some new separation axioms in bitopological spaces
Some properties of subsets, almost closed mappings and paracompactness.
Some separation axioms in fuzzy topological spaces