🌐EnglishEnglishDeutschFrançaisItalianoNederlandsPolskiPortuguêsSvenskaРусскийالعربيةفارسی한국어中文日本語EntityQ1422682· pop 21· linked from 201 articlesHadamard matrixreal square matrix whose all columns (rows) are mutually orthogonal and which only 1 or −1 as entriesAvailable in 20 languagesFrançaisDeutsch中文日本語РусскийItalianoالعربيةBelarusianCatalanCzechConnectionsinvertible matrixEntityblock matrixEntityCategoriesCombinatorial designMatrices (mathematics)Unsolved problems in mathematics