In mathematics, the Mathieu groups M11, M12, M22, M23, M24, introduced by {harvs|txt |authorlink=Émile Léonard Mathieu |last=Mathieu |year1=1861 |year2=1873}, are multiply transitive permutation groups on 11, 12, 22, 23 or 24 objects. They were the first sporadic simple groups discovered. Sometimes the notation M10, M20 and M21 is used for relat...