EntityQ3022119· pop 5· linked from 28 articlesregular semigroupSign in to savesemigroup such that, for every element x, there exists another element y such that xyx=xConnectionsmathematicsEntityInternational Standard Book NumberEntityJohn von NeumannEntitydigital object identifierEntitygroupEntityringEntityQ180686EntityJSTOREntitybibcodeEntityOxford University PressEntityintersectionEntityQ229883Entityif and only ifEntityidealEntitysemigroupEntityAmerican Mathematical SocietyEntityidempotenceEntityclassEntityHandle SystemEntityprincipal idealEntityCategoriesAlgebraic structuresSemigroup theory