X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Fcontribs%2Flambdadelta%2Fground_2%2Fynat%2Fynat_succ.ma;h=d0c7b3fdae48fff52849784dde0c35963d1b07f7;hb=1fd63df4c77f5c24024769432ea8492748b4ac79;hp=c4c989f77d6e2de9869f910d5e67e80682a702ad;hpb=2601d0c1a860fdd08c4c1d71473917aa85eeb63a;p=helm.git diff --git a/matita/matita/contribs/lambdadelta/ground_2/ynat/ynat_succ.ma b/matita/matita/contribs/lambdadelta/ground_2/ynat/ynat_succ.ma index c4c989f77..d0c7b3fda 100644 --- a/matita/matita/contribs/lambdadelta/ground_2/ynat/ynat_succ.ma +++ b/matita/matita/contribs/lambdadelta/ground_2/ynat/ynat_succ.ma @@ -12,31 +12,30 @@ (* *) (**************************************************************************) -include "ground_2/notation/functions/successor_1.ma". include "ground_2/ynat/ynat_pred.ma". (* NATURAL NUMBERS WITH INFINITY ********************************************) (* the successor function *) definition ysucc: ynat → ynat ≝ λm. match m with -[ yinj m ⇒ S m +[ yinj m ⇒ ↑m | Y ⇒ Y ]. -interpretation "ynat successor" 'Successor m = (ysucc m). +interpretation "ynat successor" 'UpArrow m = (ysucc m). -lemma ysucc_inj: ∀m:nat. ⫯m = S m. +lemma ysucc_inj: ∀m:nat. ↑(yinj m) = yinj (↑m). // qed. -lemma ysucc_Y: ⫯(∞) = ∞. +lemma ysucc_Y: ↑(∞) = ∞. // qed. (* Properties ***************************************************************) -lemma ypred_succ: ∀m. ⫰⫯m = m. +lemma ypred_succ: ∀m. ↓↑m = m. * // qed. -lemma ynat_cases: ∀n:ynat. n = 0 ∨ ∃m. n = ⫯m. +lemma ynat_cases: ∀n:ynat. n = 0 ∨ ∃m:ynat. n = ↑m. * [ * /2 width=1 by or_introl/ #n @or_intror @(ex_intro … n) // (**) (* explicit constructor *) @@ -51,17 +50,17 @@ qed. (* Inversion lemmas *********************************************************) -lemma ysucc_inv_inj: ∀m,n. ⫯m = ⫯n → m = n. +lemma ysucc_inv_inj: ∀m,n. ↑m = ↑n → m = n. #m #n #H <(ypred_succ m) <(ypred_succ n) // qed-. -lemma ysucc_inv_refl: ∀m. ⫯m = m → m = ∞. +lemma ysucc_inv_refl: ∀m. ↑m = m → m = ∞. * // #m #H lapply (yinj_inj … H) -H (**) (* destruct lemma needed *) #H elim (lt_refl_false m) // qed-. -lemma ysucc_inv_inj_sn: ∀m2,n1. yinj m2 = ⫯n1 → +lemma ysucc_inv_inj_sn: ∀m2,n1. yinj m2 = ↑n1 → ∃∃m1. n1 = yinj m1 & m2 = S m1. #m2 * normalize [ #n1 #H destruct /2 width=3 by ex2_intro/ @@ -69,30 +68,30 @@ lemma ysucc_inv_inj_sn: ∀m2,n1. yinj m2 = ⫯n1 → ] qed-. -lemma ysucc_inv_inj_dx: ∀m2,n1. ⫯n1 = yinj m2 → +lemma ysucc_inv_inj_dx: ∀m2,n1. ↑n1 = yinj m2 → ∃∃m1. n1 = yinj m1 & m2 = S m1. /2 width=1 by ysucc_inv_inj_sn/ qed-. -lemma ysucc_inv_Y_sn: ∀m. ∞ = ⫯m → m = ∞. +lemma ysucc_inv_Y_sn: ∀m. ∞ = ↑m → m = ∞. * // normalize #m #H destruct qed-. -lemma ysucc_inv_Y_dx: ∀m. ⫯m = ∞ → m = ∞. +lemma ysucc_inv_Y_dx: ∀m. ↑m = ∞ → m = ∞. /2 width=1 by ysucc_inv_Y_sn/ qed-. -lemma ysucc_inv_O_sn: ∀m. yinj 0 = ⫯m → ⊥. (**) (* explicit coercion *) +lemma ysucc_inv_O_sn: ∀m. yinj 0 = ↑m → ⊥. (**) (* explicit coercion *) #m #H elim (ysucc_inv_inj_sn … H) -H #n #_ #H destruct qed-. -lemma ysucc_inv_O_dx: ∀m. ⫯m = 0 → ⊥. +lemma ysucc_inv_O_dx: ∀m:ynat. ↑m = 0 → ⊥. /2 width=2 by ysucc_inv_O_sn/ qed-. (* Eliminators **************************************************************) lemma ynat_ind: ∀R:predicate ynat. - R 0 → (∀n:nat. R n → R (⫯n)) → R (∞) → + R 0 → (∀n:nat. R n → R (↑n)) → R (∞) → ∀x. R x. #R #H1 #H2 #H3 * // #n elim n -n /2 width=1 by/ qed-.