🌐EnglishEnglishEspañolFrançaisItalianoNederlandsPolskiPortuguêsSvenskaРусский한국어中文日本語EntityQ1834342· pop 13· linked from 246 articlesmodular groupAlso known as PSL(2;ℤ)orientation-preserving mapping class group of the torusAvailable in 13 languagesEspañolFrançais日本語РусскийPortuguêsItalianoHebrewNederlandsPolskiSvenskaUkrainianConnectionsgroup actionEntityelliptic curveEntityCategoriesAnalytic number theoryGroup theoryModular forms