
theorem Th3:
  for x being Point of I[01] st x <= 1/2 holds 2 * x is Point of I[01]
proof
  let x be Point of I[01];
  assume x <= 1/2;
  then
A1: 2 * x <= 2 * (1/2) by XREAL_1:64;
  0 <= x by BORSUK_1:43;
  hence thesis by A1,BORSUK_1:43;
end;
