Free inverse semigroups
H. E. Scheiblich · Proceedings of the American Mathematical Society · 1973
At least three authors have offered proofs of the existence of a free inverse semigroup, but without describing its structure. This paper shows that if X X is a nonempty set, G G is the group on X X , and E E is a certain subsemilattice of the power set of G G , then a certain collection of principal ideal isomorphisms of E E is a free inverse semigroup on X X .