Alas, Ofelia T.; Madriz-Mendoza, Maira; Wilson, Richard G.(Universitat Politècnica de València, 2012-04-01)
[EN] We prove some cardinal inequalities valid in the classes of Whyburn and hereditarily weakly Whyburn spaces and we construct examples of non-Whyburn and non-weakly Whyburn spaces to illustrate that some previously known ...
Alas, Ofelia T.; Wilson, Richard G.(Universitat Politècnica de València, 2011-04-01)
[EN] We study the subposet E3(X) of the lattice L1(X) of all T1-topologies on a set X, being the collections of all T3 topologies on X, with a view to deciding which elements of this partially ordered set have and which ...