🌐EnglishEnglishDeutschEspañolFrançaisItalianoNederlandsPolskiРусскийالعربيةفارسی한국어中文日本語EntityQ534131· pop 17· linked from 220 articlesroot systemgeometric arrangements of points, foundational to Lie theoryAvailable in 16 languagesFrançaisDeutsch中文日本語РусскийItalianoالعربيةCatalanGreekHungarianNederlandsConnectionsorthogonal groupEntityCoxeter groupEntityCategoriesEuclidean geometryLie algebrasLie groups