X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fbasic_2%2Fstatic%2Fsh.ma;h=bab748f7564ff60dfcab989f7cacc04ec7369abf;hb=c9a1672c725945b47f9ea8af3c23b67cf9026f01;hp=72df7717ec4eec724ca02d2d5502c8a5f7a16457;hpb=e8998d29ab83e7b6aa495a079193705b2f6743d3;p=helm.git

diff --git a/matita/matita/contribs/lambdadelta/basic_2/static/sh.ma b/matita/matita/contribs/lambdadelta/basic_2/static/sh.ma
index 72df7717e..bab748f75 100644
--- a/matita/matita/contribs/lambdadelta/basic_2/static/sh.ma
+++ b/matita/matita/contribs/lambdadelta/basic_2/static/sh.ma
@@ -12,7 +12,7 @@
 (*                                                                        *)
 (**************************************************************************)
 
-include "ground_2/arith.ma".
+include "ground_2/lib/arith.ma".
 
 (* SORT HIERARCHY ***********************************************************)
 
@@ -22,6 +22,9 @@ record sh: Type[0] ≝ {
    next_lt: ∀k. k < next k (* strict monotonicity condition *)
 }.
 
+definition sh_N: sh ≝ mk_sh S ….
+// qed.
+
 (* Basic properties *********************************************************)
 
 lemma nexts_le: ∀h,k,l. k ≤ (next h)^l k.
@@ -30,7 +33,12 @@ lapply (next_lt h ((next h)^l k)) #H
 lapply (le_to_lt_to_lt … IHl H) -IHl -H /2 width=2/
 qed.
 
+lemma nexts_lt: ∀h,k,l. k < (next h)^(l+1) k.
+#h #k #l >iter_SO
+lapply (nexts_le h k l) #H
+@(le_to_lt_to_lt … H) //
+qed.
+
 axiom nexts_dec: ∀h,k1,k2. Decidable (∃l. (next h)^l k1 = k2).
 
 axiom nexts_inj: ∀h,k,l1,l2. (next h)^l1 k = (next h)^l2 k → l1 = l2.
-