theorem
  K*`M in K*`N implies M in N
proof
  assume that
A1: K*`M in K*`N and
A2: not M in N;
  N c= M by A2,CARD_1:4;
  then K*`N c= K*`M by Th89;
  hence thesis by A1,CARD_1:4;
end;
