Free submonoids in the monoid of languages Original Research Article

The monoid of language M is the family of languages M = {A ¦0 ≠ ⊆ X+ or A = {1}}, where X+ is the free semigroup generated by the finite alphabet X containing more than one letter and l is the empty word. This paper is a study of free submonoids in M. We found a free submonoid of M which contains the family of all finite prefix codes.