reserve m for Cardinal,
  A,B,C for Ordinal,
  x,y,z,X,Y,Z,W for set,
  f for Function;

theorem
  m in card Tarski-Class W implies m in Tarski-Class W
proof
  assume m in card Tarski-Class W;
  then m in On Tarski-Class W by Th9;
  hence thesis by ORDINAL1:def 9;
end;
