Modifications of closure collections
Modifications of closure collections
Modified Whyburn semigroups.
Modular, distributive and simple intervals of the lattice of topologies
More on sg-compact spaces.
More on strongly sequential spaces
Strongly sequential spaces were introduced and studied to solve a problem of Tanaka concerning the product of sequential topologies. In this paper, further properties of strongly sequential spaces are investigated.
More on the product of pseudo radial spaces
It is proved that the product of two pseudo radial compact spaces is pseudo radial provided that one of them is monolithic.
More on tie-points and homeomorphism in ℕ*
A point x is a (bow) tie-point of a space X if X∖x can be partitioned into (relatively) clopen sets each with x in its closure. We denote this as where A, B are the closed sets which have a unique common accumulation point x. Tie-points have appeared in the construction of non-trivial autohomeomorphisms of βℕ = ℕ* (by Veličković and Shelah Steprans) and in the recent study (by Levy and Dow Techanie) of precisely 2-to-1 maps on ℕ*. In these cases the tie-points have been the unique fixed point...
More on -closed sets in topological spaces.
More reflections on compactness
We consider the question of when , where is the elementary submodel topology on X ∩ M, especially in the case when is compact.
More topological cardinal inequalities
A new topological cardinal invariant is defined; it may be considered as a weaker form of the Lindelöf degree.