
theorem Th7:
  for x being Point of I[01] st x >= 1/2 holds x - 1/4 is Point of I[01]
proof
  let x be Point of I[01];
  x <= 1 by BORSUK_1:43;
  then x <= 1 + 1/4 by XXREAL_0:2;
  then
A1: x - 1/4 <= 1 by XREAL_1:20;
  assume x >= 1/2;
  then x >= 1/4 + 0 by XXREAL_0:2;
  then x - 1/4 >= 0 by XREAL_1:19;
  hence thesis by A1,BORSUK_1:43;
end;
