monoid (original) (raw)

A monoid is a semigroupPlanetmathPlanetmath G which contains an identity elementMathworldPlanetmath; that is, there exists an element e∈G such that e⋅a=a⋅e=a for all a∈G.

If e and f are identity elements of a monoid G, then e=e⋅f=f⋅e=f, so we may speak of “the” identity element of G.

A monoid homomorphism from monoids G to H is a semigroup homomorphism f:G→H such that f⁢(eG)=eH, where eG,eH are identity elements of G and H respectively.

Title monoid
Canonical name Monoid
Date of creation 2013-03-22 11:50:15
Last modified on 2013-03-22 11:50:15
Owner djao (24)
Last modified by djao (24)
Numerical id 9
Author djao (24)
Entry type Definition
Classification msc 20M99
Classification msc 34-01
Synonym homomorphismPlanetmathPlanetmathPlanetmathPlanetmathPlanetmathPlanetmath
Related topic Semigroup
Defines monoid homomorphism