is not subsequential
If a separable dense in itself metric space is not a union of countably many nowhere dense subsets, then its -space is not subsequential.
Characterizations of Sn-metrizable Spaces
Closure spaces and characterizations of filters in terms of their Stone images
Fréchet, strongly Fréchet, productively Fréchet, weakly bisequential and bisequential filters (i.e., neighborhood filters in spaces of the same name) are characterized in a unified manner in terms of their images in the Stone space of ultrafilters. These characterizations involve closure structures on the set of ultrafilters. The case of productively Fréchet filters answers a question of S. Dolecki and turns out to be the only one involving a non topological closure structure.
Completion of sequential Cauchy spaces
Concerning Splittability and Perfect Mappings
Connectivity properties of sequential Boolean algebras
Contractive fixed points
Criterios De Convergencia Secuencial.