EntityQ3022118· pop 5· linked from 32 articlesinverse semigroupSign in to saveregular semigroup in which every element has a unique inverseConnectionsbijectionEntityimageEntitypartially ordered setEntitytotal orderEntitycongruence relationEntityViktor WagnerEntityUnited KingdomCountrySoviet UnionConceptInternational Standard Book NumberEntityfunctionEntitysetEntitydigital object identifierEntitygroupEntityempty setEntitysubsetEntityassociativityEntitybinary operationEntityJSTOROrganizationunionEntityisomorphismEntityCategoriesAlgebraic structuresSemigroup theory