🌐EnglishEnglishDeutschEspañolFrançaisItalianoNederlandsPolskiPortuguêsTürkçeРусский한국어中文日本語EntityQ372037· pop 14· linked from 35 articlesSeifert–van Kampen theorema theorem in topology describing the fundamental group of a space in terms of a cover of the space by two open path-connected subspacesConnectionsconnected spaceEntityhomotopyEntityCategoriesHomotopy theoryTheorems in algebraic topology