X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=matita%2Fmatita%2Flib%2Flambda%2Freduction.ma;h=e6a122c85581f9e91e36ac203691b3b2a7744f9a;hb=bb397726bff29389cdcb649a8c37484395b3b85e;hp=e6d57ba6ec5077089f924a30396d36ec462e7d64;hpb=fb9f80d2fb30216cc0754e8e8d09206f3e3e7bb7;p=helm.git diff --git a/matita/matita/lib/lambda/reduction.ma b/matita/matita/lib/lambda/reduction.ma index e6d57ba6e..e6a122c85 100644 --- a/matita/matita/lib/lambda/reduction.ma +++ b/matita/matita/lib/lambda/reduction.ma @@ -9,7 +9,7 @@ \ / V_______________________________________________________________ *) -include "lambda/subterms.ma". +include "lambda/par_reduction.ma". (* inductive T : Type[0] ≝ @@ -21,436 +21,24 @@ inductive T : Type[0] ≝ | D: T →T . *) -let rec is_dummy M ≝ -match M with - [D P ⇒ true - |_ ⇒ false - ]. - -let rec is_lambda M ≝ -match M with - [Lambda P Q ⇒ true - |_ ⇒ false - ]. - -theorem is_dummy_to_exists: ∀M. is_dummy M = true → -∃N. M = D N. -#M (cases M) normalize - [1,2: #n #H destruct|3,4,5: #P #Q #H destruct - |#N #_ @(ex_intro … N) // - ] -qed. - -theorem is_lambda_to_exists: ∀M. is_lambda M = true → -∃P,N. M = Lambda P N. -#M (cases M) normalize - [1,2,6: #n #H destruct|3,5: #P #Q #H destruct - |#P #N #_ @(ex_intro … P) @(ex_intro … N) // - ] -qed. - -inductive pr : T →T → Prop ≝ - | beta: ∀P,M,N,M1,N1. pr M M1 → pr N N1 → - pr (App (Lambda P M) N) (M1[0 ≝ N1]) - | dapp: ∀M,N,P. pr (App M N) P → - pr (App (D M) N) (D P) - | dlam: ∀M,N,P. pr (Lambda M N) P → pr (Lambda M (D N)) (D P) - | none: ∀M. pr M M - | appl: ∀M,M1,N,N1. pr M M1 → pr N N1 → pr (App M N) (App M1 N1) - | lam: ∀P,P1,M,M1. pr P P1 → pr M M1 → - pr (Lambda P M) (Lambda P1 M1) - | prod: ∀P,P1,M,M1. pr P P1 → pr M M1 → - pr (Prod P M) (Prod P1 M1) - | d: ∀M,M1. pr M M1 → pr (D M) (D M1). - -lemma prSort: ∀M,n. pr (Sort n) M → M = Sort n. -#M #n #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |// - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prRel: ∀M,n. pr (Rel n) M → M = Rel n. -#M #n #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |// - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prD: ∀M,N. pr (D N) M → ∃P.M = D P ∧ pr N P. -#M #N #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#R #eqR eqN1 #pr3 - @or_intror @(ex_intro … S) @(ex_intro … N2) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prApp_lambda: -∀Q,M,N,P. pr (App (Lambda Q M) N) P → -∃M1,N1. (P = M1[0:=N1] ∧ pr M M1 ∧ pr N N1) ∨ - (P = (App M1 N1) ∧ pr (Lambda Q M) M1 ∧ pr N N1). -#Q #M #N #P #prH (inversion prH) - [#R #M #N #M1 #N1 #pr1 #pr2 #_ #_ #H destruct #_ - @(ex_intro … M1) @(ex_intro … N1) /4/ - |#M1 #N1 #P1 #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#R #eqR #_ @(ex_intro … (Lambda Q M)) @(ex_intro … N) /4/ - |#M1 #N1 #M2 #N2 #pr1 #pr2 #_ #_ #H destruct #_ - @(ex_intro … N1) @(ex_intro … N2) /4/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prLambda_not_dummy: ∀M,N,P. pr (Lambda M N) P → is_dummy N = false → -∃M1,N1. (P = Lambda M1 N1 ∧ pr M M1 ∧ pr N N1). -#M #N #P #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct #_ #eqH destruct - |#Q #eqProd #_ #_ @(ex_intro … M) @(ex_intro … N) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#Q #Q1 #S #S1 #pr1 #pr2 #_ #_ #H #H1 #_ destruct - @(ex_intro … Q1) @(ex_intro … S1) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prLambda_dummy: ∀M,N,P. pr (Lambda M (D N)) P → - (∃M1,N1. P = Lambda M1 (D N1) ∧ pr M M1 ∧ pr N N1) ∨ - (∃Q. (P = D Q ∧ pr (Lambda M N) Q)). -#M #N #P #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M1 #N1 #P1 #prM #_ #eqlam destruct #H @or_intror - @(ex_intro … P1) /3/ - |#Q #eqLam #_ @or_introl @(ex_intro … M) @(ex_intro … N) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#Q #Q1 #S #S1 #pr1 #pr2 #_ #_ #H #H1 destruct - cases (prD …pr2) #S2 * #eqS1 #pr3 >eqS1 @or_introl - @(ex_intro … Q1) @(ex_intro … S2) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prLambda: ∀M,N,P. pr (Lambda M N) P → -(∃M1,N1. (P = Lambda M1 N1 ∧ pr M M1 ∧ pr N N1)) ∨ -(∃N1,Q. (N=D N1) ∧ (P = (D Q) ∧ pr (Lambda M N1) Q)). -#M #N #P #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M1 #N1 #P1 #prM1 #_ #eqlam #eqP destruct @or_intror - @(ex_intro … N1) @(ex_intro … P1) /3/ - |#Q #eqProd #_ @or_introl @(ex_intro … M) @(ex_intro … N) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#Q #Q1 #S #S1 #pr1 #pr2 #_ #_ #H #H1 destruct @or_introl - @(ex_intro … Q1) @(ex_intro … S1) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #N #_ #_ #H destruct - ] -qed. - -lemma prProd: ∀M,N,P. pr (Prod M N) P → -∃M1,N1. P = Prod M1 N1 ∧ pr M M1 ∧ pr N N1. -#M #N #P #prH (inversion prH) - [#P #M #N #M1 #N1 #_ #_ #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#M #N #P1 #_ #_ #H destruct - |#Q #eqProd #_ @(ex_intro … M) @(ex_intro … N) /3/ - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#M #M1 #N #N1 #_ #_ #_ #_ #H destruct - |#Q #Q1 #S #S1 #pr1 #pr2 #_ #_ #H #H1 destruct - @(ex_intro … Q1) @(ex_intro … S1) /3/ - |#M #N #_ #_ #H destruct - ] +inductive red : T →T → Prop ≝ + | rbeta: ∀P,M,N. red (App (Lambda P M) N) (M[0 ≝ N]) + | rdapp: ∀M,N. red (App (D M) N) (D (App M N)) + | rdlam: ∀M,N. red (Lambda M (D N)) (D (Lambda M N)) + | rappl: ∀M,M1,N. red M M1 → red (App M N) (App M1 N) + | rappr: ∀M,N,N1. red N N1 → red (App M N1) (App M N1) + | rlaml: ∀M,M1,N. red M M1 → red (Lambda M N) (Lambda M1 N) + | rlamr: ∀M,N,N1. red N N1 → red(Lambda M N1) (Lambda M N1) + | rprodl: ∀M,M1,N. red M M1 → red (Prod M N) (Prod M1 N) + | rprodr: ∀M,N,N1. red N N1 → red (Prod M N1) (Prod M N1) + | d: ∀M,M1. red M M1 → red (D M) (D M1). + +lemma red_to_pr: ∀M,N. red M N → pr M N. +#M #N #redMN (elim redMN) /2/ qed. -let rec full M ≝ - match M with - [ Sort n ⇒ Sort n - | Rel n ⇒ Rel n - | App P Q ⇒ full_app P (full Q) - | Lambda P Q ⇒ full_lam (full P) Q - | Prod P Q ⇒ Prod (full P) (full Q) - | D P ⇒ D (full P) - ] -and full_app M N ≝ - match M with - [ Sort n ⇒ App (Sort n) N - | Rel n ⇒ App (Rel n) N - | App P Q ⇒ App (full_app P (full Q)) N - | Lambda P Q ⇒ (full Q) [0 ≝ N] - | Prod P Q ⇒ App (Prod (full P) (full Q)) N - | D P ⇒ D (full_app P N) - ] -and full_lam M N on N≝ - match N with - [ Sort n ⇒ Lambda M (Sort n) - | Rel n ⇒ Lambda M (Rel n) - | App P Q ⇒ Lambda M (full_app P (full Q)) - | Lambda P Q ⇒ Lambda M (full_lam (full P) Q) - | Prod P Q ⇒ Lambda M (Prod (full P) (full Q)) - | D P ⇒ D (full_lam M P) - ] -. -axiom pr_subst_lam: ∀Q,M,M1,N,N1,n. pr (Lambda Q M) M1 → pr N N1 → - pr (Lambda Q M)[n≝N] M1[n≝N1]. -(* -#Q #M (elim M) - [#i #M1 #N #N1 #n #pr1 #pr2 - (cases (prLambda_not_dummy … pr1 ?)) // - #M2 * #N2 * * #eqM1 #pr3 #pr4 >eqM1 normalize @lam // *) -(* - cases(prLambda … pr1); - [* #M2 * #N2 * * #eqM2 #pr3 #pr4 >eqM2 normalize - @lam; [@Hind1 // | @Hind2 // ] - |* #M2 * #Q1 * #eqM * #eqM1 #pr3 >eqM >eqM1 - normalize @dlam *) -(* axiom pr_subst: ∀M,M1,N,N1. pr M M1 → pr N N1 → - pr M[0≝N] M1[0≝N1]. *) - -theorem pr_subst: ∀M,M1,N,N1,n. pr M M1 → pr N N1 → - pr M[n≝N] M1[n≝N1]. -#M (elim M) - [#i #M1 #N #N1 #n #pr1 #pr2 normalize >(prSort … pr1) // - |#i #M1 #N #N1 #n #pr1 #pr2 >(prRel … pr1) - (* gran casino - normalize (cases n) // *) - |#Q #M #Hind1 #Hind2 #M1 #N #N1 #pr1 #pr2 - |#Q #M #Hind1 #Hind2 #M1 #N #N1 #n #pr1 #pr2 - @pr_subst_lam // - |#Q #M #Hind1 #Hind2 #M1 #N #N1 #n #pr1 #pr2 - (cases (prProd … pr1)) #M2 * #N2 * * #eqM1 #pr3 #pr4 >eqM1 - @prod [@Hind1 // | @Hind2 // ] - |#Q #Hind #M1 #N #N1 #n #pr1 #pr2 (cases (prD … pr1)) - #M2 * #eqM1 #pr1 >eqM1 @d @Hind // - ] - -lemma pr_full_app: ∀M,N,N1. pr N N1 → - (∀S.subterm S M → pr S (full S)) → - pr (App M N) (full_app M N1). -#M (elim M) normalize /2/ - [#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @appl // @Hind1 /3/ - |#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @beta /2/ - |#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @appl // @prod /2/ - |#P #Hind #N1 #N2 #prN #H @dapp @Hind /3/ - ] -qed. - -lemma pr_full_lam: ∀M,N,N1. pr N N1 → - (∀S.subterm S M → pr S (full S)) → - pr (Lambda N M) (full_lam N1 M). -#M (elim M) normalize /2/ - [#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @lam // @pr_full_app /3/ - |#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @lam // @Hind2 /3/ - |#P #Q #Hind1 #Hind2 #N1 #N2 #prN #H @lam // @prod /2/ - |#P #Hind #N1 #N2 #prN #H @dlam @Hind /3/ - ] -qed. - -theorem pr_full: ∀M. pr M (full M). -@Telim #M (cases M) - [// - |// - |#M1 #N1 #H @pr_full_app /3/ - |#M1 #N1 #H @pr_full_lam /3/ - |#M1 #N1 #H @prod /2/ - |#P #H @d /2/ - ] -qed. - -lemma complete_beta: ∀Q,N,N1,M,M1.(* pr N N1 → *) pr N1 (full N) → - (∀S,P.subterm S (Lambda Q M) → pr S P → pr P (full S)) → - pr (Lambda Q M) M1 → pr (App M1 N1) ((full M) [O ≝ (full N)]). -#Q #N #N1 #M (elim M) - [1,2:#n #M1 #prN1 #sub #pr1 - (cases (prLambda_not_dummy … pr1 ?)) // #M2 * #N2 - * * #eqM1 #pr3 #pr4 >eqM1 @beta /3/ - |3,4,5:#M1 #M2 #_ #_ #M3 #prN1 #sub #pr1 - (cases (prLambda_not_dummy … pr1 ?)) // #M4 * #N3 - * * #eqM3 #pr3 #pr4 >eqM3 @beta /3/ - |#M1 #Hind #M2 #prN1 #sub #pr1 - (cases (prLambda_dummy … pr1)) - [* #M3 * #N3 * * #eqM2 #pr3 #pr4 >eqM2 - @beta // normalize @d @sub /2/ - |* #P * #eqM2 #pr3 >eqM2 normalize @dapp - @Hind // #S #P #subH #pr4 @sub // - (cases (sublam … subH)) [* [* /2/ | /2/] | /3/ - ] - ] -qed. -lemma complete_beta1: ∀Q,N,M,M1. - (∀N1. pr N N1 → pr N1 (full N)) → - (∀S,P.subterm S (Lambda Q M) → pr S P → pr P (full S)) → - pr (App (Lambda Q M) N) M1 → pr M1 ((full M) [O ≝ (full N)]). -#Q #N #M #M1 #prH #subH #prApp -(cases (prApp_lambda … prApp)) #M2 * #N2 * - [* * #eqM1 #pr1 #pr2 >eqM1 @pr_subst; [@subH // | @prH //] - |* * #eqM1 #pr1 #pr2 >eqM1 @(complete_beta … pr1); - [@prH // - |#S #P #subS #prS @subH // - ] - ] -qed. - -lemma complete_app: ∀M,N,P. - (∀S,P.subterm S (App M N) → pr S P → pr P (full S)) → - pr (App M N) P → pr P (full_app M (full N)). -#M (elim M) normalize - [#n #P #Q #Hind #pr1 - cases (prApp_not_dummy_not_lambda … pr1 ??) // - #M1 * #N1 * * #eqQ #pr1 #pr2 >eqQ @appl; - [@(Hind (Sort n)) // |@Hind //] - |#n #P #Q #Hind #pr1 - cases (prApp_not_dummy_not_lambda … pr1 ??) // - #M1 * #N1 * * #eqQ #pr1 #pr2 >eqQ @appl; - [@(Hind (Rel n)) // |@Hind //] - |#P #Q #Hind1 #Hind2 #N1 #N2 #subH #prH - cases (prApp_not_dummy_not_lambda … prH ??) // - #M2 * #N2 * * #eqQ #pr1 #pr2 >eqQ @appl; - [@Hind1 /3/ |@subH //] - |#P #Q #Hind1 #Hind2 #N1 #P2 #subH #prH - @(complete_beta1 … prH); - [#N2 @subH // | #S #P1 #subS @subH - (cases (sublam … subS)) [* [* /2/ | /2/] | /2/] - ] - |#P #Q #Hind1 #Hind2 #N1 #N2 #subH #prH - cases (prApp_not_dummy_not_lambda … prH ??) // - #M2 * #N2 * * #eqQ #pr1 #pr2 >eqQ @appl; - [@(subH (Prod P Q)) // |@subH //] - |#P #Hind #N1 #N2 #subH #prH - (cut (∀S. subterm S (App P N1) → subterm S (App (D P) N1))) - [#S #sub (cases (subapp …sub)) [* [ * /2/ | /3/] | /2/]] #Hcut - cases (prApp_D … prH); - [* #N3 * #eqN3 #pr1 >eqN3 @d @Hind // - #S #P1 #sub1 #prS @subH /2/ - |* #N3 * #N4 * * #eqN2 #prP #prN1 >eqN2 @dapp @Hind; - [#S #P1 #sub1 #prS @subH /2/ |@appl // ] - ] - ] -qed. - -lemma complete_lam: ∀M,Q,M1. - (∀S,P.subterm S (Lambda Q M) → pr S P → pr P (full S)) → - pr (Lambda Q M) M1 → pr M1 (full_lam (full Q) M). -#M (elim M) - [#n #Q #M1 #sub #pr1 normalize - (cases (prLambda_not_dummy … pr1 ?)) // #M2 * #N2 - * * #eqM1 #pr3 #pr4 >eqM1 @lam; - [@sub /2/ | @(sub (Sort n)) /2/] - |#n #Q #M1 #sub #pr1 normalize - (cases (prLambda_not_dummy … pr1 ?)) // #M2 * #N2 - * * #eqM1 #pr3 #pr4 >eqM1 @lam; - [@sub /2/ | @(sub (Rel n)) /2/] - |#M1 #M2 #_ #_ #M3 #Q #sub #pr1 - (cases (prLambda_not_dummy … pr1 ?)) // #M4 * #N3 - * * #eqM3 #pr3 #pr4 >eqM3 @lam; - [@sub // | @complete_app // #S #P1 #subS @sub - (cases (subapp …subS)) [* [* /2/ | /2/] | /3/ ] - ] - |#M1 #M2 #_ #Hind #M3 #Q #sub #pr1 - (cases (prLambda_not_dummy … pr1 ?)) // #M4 * #N3 - * * #eqM3 #pr3 #pr4 >eqM3 @lam; - [@sub // |@Hind // #S #P1 #subS @sub - (cases (sublam …subS)) [* [* /2/ | /2/] | /3/ ] - ] - |#M1 #M2 #_ #_ #M3 #Q #sub #pr1 - (cases (prLambda_not_dummy … pr1 ?)) // #M4 * #N3 - * * #eqM3 #pr3 #pr4 >eqM3 @lam; - [@sub // | (cases (prProd … pr4)) #M5 * #N4 * * #eqN3 - #pr5 #pr6 >eqN3 @prod; - [@sub /3/ | @sub /3/] - ] - |#P #Hind #Q #M2 #sub #pr1 (cases (prLambda_dummy … pr1)) - [* #M3 * #N3 * * #eqM2 #pr3 #pr4 >eqM2 normalize - @dlam @Hind; - [#S #P1 #subS @sub (cases (sublam …subS)) - [* [* /2/ | /2/ ] |/3/ ] - |@lam // - ] - |* #P * #eqM2 #pr3 >eqM2 normalize @d - @Hind // #S #P #subH @sub - (cases (sublam … subH)) [* [* /2/ | /2/] | /3/] - ] - ] -qed. - -theorem complete: ∀M,N. pr M N → pr N (full M). -@Telim #M (cases M) - [#n #Hind #N #prH normalize >(prSort … prH) // - |#n #Hind #N #prH normalize >(prRel … prH) // - |#M #N #Hind #Q @complete_app - #S #P #subS @Hind // - | #P #P1 #Hind #N #Hpr @(complete_lam … Hpr) - #S #P #subS @Hind // - |5: #P #P1 #Hind #N #Hpr - (cases (prProd …Hpr)) #M1 * #N1 * * #eqN >eqN normalize /3/ - |6:#N #Hind #P #prH normalize cases (prD … prH) - #Q * #eqP >eqP #prN @d @Hind // - ] -qed. - -theorem diamond: ∀P,Q,R. pr P Q → pr P R → ∃S. -pr Q S ∧ pr P S. -#P #Q #R #pr1 #pr2 @(ex_intro … (full P)) /3/ -qed.