RENDICONTI DEL CIRCOLO MATEMATICO DI PALERMO, vol.64, no.3, pp.341-346, 2015 (ESCI)
Let a be an automorphism of a finite group G and assume that G = {[g, alpha] : g is an element of G} . C-G(alpha). We prove that the order of the subgroup [G, alpha] is bounded above by n(log2(n+1)) where n is the index of C-G(alpha) in G.