Precise bounds for the sequential order of products of some Fréchet topologies
Expressing the sequential order of a product topology in terms of fascicularity and sagittality of the component topologies, the authors get lower bounds, upper bounds and precise bounds for the sequential order of the product of two regular Fréchet topologies, of two subtransverse topologies and of two Lashnev topologies, respectively. Further they show that for every countable ordinal \(\alpha\), there exists a Lashnev topology such that the sequential order of its square is equal to \(\alpha\).
scientific article; zbMATH DE number 1308011