2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/116495C-cross topologies are introduced. Modifcations of the Kuratowski-Ulam Theorem are considered. Cardinal invariants add, cof, cov and non with respect to meager or nowhere dense subsets are compared. Remarks on invariants cof(nwdY) are mentioned for dense subspaces Y of X.11 pagesGeneral TopologyPrimary: 54A10; Secondary: 03E17, 54E52text