reserve f,f1,f2,g for PartFunc of REAL,REAL;
reserve A for non empty closed_interval Subset of REAL;
reserve p,r,x,x0 for Real;
reserve n for Element of NAT;
reserve Z for open Subset of REAL;

theorem
  for r being Real holds rng (REAL --> r) c= REAL
proof
  let r be Real;
  rng (REAL --> r) c= {r} by FUNCOP_1:13;
  hence thesis by XBOOLE_1:1;
end;
