🌐EnglishEnglishFrançaisPortuguêsРусский한국어中文日本語EntityQ4720484· pop 5· linked from 12 articlesAlexander dualityduality of the homology of the complement of a subspaceAvailable in 5 languagesFrançais中文Русский한국어via Wikidata sitelinks · CC0Connectionscontractible spaceEntitymathematicsEntityCategoriesAlgebraic topologyDuality (mathematics)