Universal embedding theorem: If G is an extension of A by H, then there exists a subgroup of the unrestricted wreath product A≀H which is isomorphic to G.M. Krasner and L. Kaloujnine, "Produit complet des groupes de permutations et le problème d'extension de groupes III", Acta Sci. Math. 14, pp. 69–82 (1951) This is also known as the Krasner–Kaloujnine embedding theorem. The Krohn–Rhodes theorem involves what is basically the semigroup equivalent of this.
universal embedding theorem if g is an extension of a by h then there exists a subgroup of the unrestricted wreath product a≀h which is isomorphic to gm krasner and l kaloujnine "produit complet des groupes de permutations et le problème d'extension de groupes iii" acta sci math 14 pp 69–82 (1951) this is also known as the krasner–kaloujnine embedding theorem the krohn–rhodes theorem involves what is basically the semigroup equivalent of this