🌐한국어EnglishEspañolFrançaisPortuguêsTiếng ViệtРусскийالعربية한국어中文日本語EntityQ1363919· pop 12· linked from 184 articles제2 가산 공간Also known as completely separable space, second axiom of countabilitytopological space whose topology admits a countable baseAvailable in 12 languagesEspañolFrançais中文日本語РусскийCatalanDanishGalicianTiếng ViệtUkrainianConnectionsmetrizable spaceEntityquotient topological spaceEntityCategoriesGeneral topologyProperties of topological spaces