theorem
  A <> {} & (for g1,g2 st g1 in A & g2 in A holds g1 * g2 in A) & (for
  g1 st g1 in A holds g1" in A) & (for o,g1 st g1 in A holds (G^o).g1 in A)
implies ex H being strict StableSubgroup of G st the carrier of H = A by Lm14;
