+++ /dev/null
-(**************************************************************************)
-(* ___ *)
-(* ||M|| *)
-(* ||A|| A project by Andrea Asperti *)
-(* ||T|| *)
-(* ||I|| Developers: *)
-(* ||T|| The HELM team. *)
-(* ||A|| http://helm.cs.unibo.it *)
-(* \ / *)
-(* \ / This file is distributed under the terms of the *)
-(* v GNU General Public License Version 2 *)
-(* *)
-(**************************************************************************)
-
-include "ground/arith/ynat_plus.ma".
-include "ground/arith/ynat_minus1.ma".
-include "ground/arith/ynat_lt_pred_succ.ma".
-
-(* STRICT ORDER FOR NON-NEGATIVE INTEGERS WITH INFINITY *********************)
-
-(* Constructions with yminus1 and yplus *************************************)
-
-(*** ylt_plus1_to_minus_inj2 *)
-lemma ylt_plus_sn_dx_minus1_dx (n) (x) (z):
- x + yinj_nat n < z → x < z - n.
-#n @(nat_ind_succ … n) -n //
-#n #IH #x #z >ysucc_inj <yplus_succ_shift
-/3 width=1 by ylt_des_succ_sn/
-qed.
-
-(*** ylt_plus1_to_minus_inj1 *)
-lemma ylt_plus_sn_sn_minus1_dx (n) (x) (z):
- yinj_nat n + x < z → x < z - n.
-/2 width=1 by ylt_plus_sn_dx_minus1_dx/ qed.