theorem
  (canonical_homomorphism T).(h.t) =
  (canonical_homomorphism T).(h.@((canonical_homomorphism T).t))
  proof
    set H = canonical_homomorphism T;
    consider g being Endomorphism of T such that
A1: H**h = g**H &
    for t being Element of T holds g.t = H.(h.@t) by Th86;
    thus H.(h.t) = (H**h).t by Th14 .= g.(H.t) by A1,Th14 .= H.(h.@(H.t))
    by A1;
  end;
