 reserve G for Group;
 reserve H for Subgroup of G;
 reserve a, b, c, x, y for Element of G;
 reserve h for Homomorphism of G, G;
 reserve q, q1 for set;

theorem Th3:
  id the carrier of G is Element of Aut G
proof
  id the carrier of G is Homomorphism of G, G by GROUP_6:38;
  then consider h such that
A1: h = id the carrier of G;
  rng h = the carrier of G by A1,RELAT_1:45;
  then h is onto;
  hence thesis by A1,Def1;
end;
