reserve m,n for Nat;
reserve r for Real;
reserve c for Element of F_Complex;

theorem Th3:
  for A being positive Real
  ex n being positive Nat st 1/(2|^n) <= A
  proof
    let A be positive Real;
    consider n being positive Nat such that
A1: 1/A <= 2|^n by Th2;
    take n;
    1/(1/A) >= 1/(2|^n) by A1,XREAL_1:118;
    hence thesis;
  end;
