🌐EnglishEnglishDeutschFrançaisItalianoNederlandsPolskiPortuguêsSvenskaРусский中文日本語EntityQ1991239· pop 13· linked from 17 articlesErdős conjecture on arithmetic progressionsCharacterization of large setsConnectionsInternational Standard Book NumberEntitydigital object identifierEntityCategoriesCombinatoricsConjecturesUnsolved problems in mathematics