theorem
  { t } is AntiChain_of_Prefixes of T
proof reconsider S = { t } as AntiChain_of_Prefixes by Th35;
 S is AntiChain_of_Prefixes of T
  proof
    let x be object;
    assume x in S;
then  x = t by TARSKI:def 1;
    hence thesis;
  end;
  hence thesis;
end;
