EntityQ1363919· pop 12· linked from 184 articlessecond-countable spaceSign in to savetopological space whose topology admits a countable baseConnectionsmetrizable spaceEntityquotient topological spaceEntitymathematicsEntityInternational Standard Book NumberEntitytopologyEntityrational numberEntitycontinuous functionEntityEuclidean spaceEntitymetric spaceEntitytopological spaceEntitymanifoldEntitycardinalityEntityalgebraic topologyEntityballEntityPoincaré conjectureEntityKlein bottleEntitycountable setEntityopen setEntityimageEntityEuler characteristicEntityCategoriesGeneral topologyProperties of topological spaces