
theorem Th6:
  for A1,A2 being AdjectiveStr st the AdjectiveStr of A1 = the
  AdjectiveStr of A2 holds A1 is without_fixpoints implies A2 is
  without_fixpoints
proof
  let A1,A2 be AdjectiveStr such that
A1: the AdjectiveStr of A1 = the AdjectiveStr of A2;
  assume
A2: not ex a being adjective of A1 st non-a = a;
  given a being adjective of A2 such that
A3: non-a = a;
  reconsider b = a as adjective of A1 by A1;
  non-b = b by A1,A3;
  hence contradiction by A2;
end;
