reserve X,Y,Z,x,y,z for set;
reserve T,R for Tolerance of X;

theorem
  for x st x in X holds {x} is TolSet of T
proof
  let x;
  assume x in X;
  then [x,x] in T by Th7;
  then {x,x} is TolSet of T by Th15;
  hence thesis by ENUMSET1:29;
end;
