anchor.diff:                  if l = ptm && is_realintconst r && Choice.get (dest_realintconst r) >/ num_0 then 
                       return! REFL tm
                   else 
  -                    return! fail()
  +                    return! Choice.fail()
               }
               |> Choice.mapError (fun e -> nestedFailure e "REAL_RAT_NEG_CONV"))
   
  
positive.code: (* ------------------------------------------------------------------------- *)
  (* Everything.                                                               *)
  (* ------------------------------------------------------------------------- *)
  /// Performs one arithmetic or relational operation on rational literals of type :real.
  let REAL_RAT_RED_CONV = 
      let gconv_net = 
  
negative.code:         prove
              ((parse_term @"&0 < y1 ==> &0 < y2 ==> ((x1 / y1 = x2 / y2) <=> (x1 * y2 = x2 * y1))"), 
               REWRITE_TAC [IMP_IMP; RAT_LEMMA5])
  
      let x1 = (parse_term @"x1:real")
      let x2 = (parse_term @"x2:real")
      let y1 = (parse_term @"y1:real")
  