2 ||M|| This file is part of HELM, an Hypertextual, Electronic
3 ||A|| Library of Mathematics, developed at the Computer Science
4 ||T|| Department of the University of Bologna, Italy.
7 ||A|| This file is distributed under the terms of the
8 \ / GNU General Public License Version 2
10 V_______________________________________________________________ *)
12 include "lambda-delta/syntax/weight.ma".
13 include "lambda-delta/reduction/pr_lift.ma".
15 (* SINGLE STEP PARALLEL REDUCTION ON TERMS **********************************)
17 (* Confluence lemmas ********************************************************)
19 lemma pr_conf_sort_sort: ∀L,k1. ∃∃T0. L ⊢ (⋆k1) ⇒ T0 & L ⊢ (⋆k1) ⇒ T0.
22 lemma pr_conf_lref_lref: ∀L,i1. ∃∃T0. L ⊢ (#i1) ⇒ T0 & L ⊢ (#i1) ⇒ T0.
25 lemma pr_conf_bind_bind:
26 ∀L,I1,V11,V12,T11,T12,V22,T22. (
27 ∀L1,T1. #L1 + #T1 < #L + (#V11 + #T11 + 1) →
28 ∀T3,T4. L1 ⊢ T1 ⇒ T3 → L1 ⊢ T1 ⇒ T4 →
29 ∃∃T0. L1 ⊢ T3 ⇒ T0 & L1 ⊢ T4 ⇒ T0
31 L ⊢ V11 ⇒ V12 → L. 𝕓{I1} V11 ⊢ T11 ⇒ T12 →
32 L ⊢ V11 ⇒ V22 → L. 𝕓{I1} V11 ⊢ T11 ⇒ T22 →
33 ∃∃T0. L ⊢ 𝕓{I1} V12. T12 ⇒ T0 & L ⊢ 𝕓{I1} V22. T22 ⇒ T0.
34 #L #I1 #V11 #V12 #T11 #T12 #V22 #T22 #IH #HV1 #HT1 #HV2 #HT2
35 elim (IH … HV1 … HV2) [2: /2/ ] #V #HV1 #HV2
36 elim (IH … HT1 … HT2) [2: normalize // ] -HT1 HT2 T11 IH #T #HT1 #HT2
37 @ex2_1_intro [2: @pr_bind [3: @HV1 |1: skip |4:
39 (* Confluence ***************************************************************)
43 ∀L1,T1. #[L1, T1] < #[L, T] →
44 ∀T3,T4. L1 ⊢ T1 ⇒ T3 → L1 ⊢ T1 ⇒ T4 →
45 ∃∃T0. L1 ⊢ T3 ⇒ T0 & L1 ⊢ T4 ⇒ T0
47 ∀K1,U1,T1,K2,U2,T2. K1 ⊢ U1 ⇒ T1 → K2 ⊢ U2 ⇒ T2 →
48 K1 = L → U1 = T → K2 = L → U2 = T →
49 ∃∃T0. L ⊢ T1 ⇒ T0 & L ⊢ T2 ⇒ T0.
50 #L #T #IH #K1 #U1 #T1 #K2 #U2 #T2
53 (* case 1: sort, sort *)
54 [ #K2 #k2 #H1 #H2 #H3 #H4 destruct -K1 K2 T k2 //
55 (* case 2: sort, lref (excluded) *)
56 | #K2 #i2 #H1 #H2 #H3 #H4 destruct
57 (* case 3: sort, bind (excluded) *)
58 | #K2 #I2 #V21 #V22 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
59 (* case 4: sort, flat (excluded) *)
60 | #K2 #I2 #V21 #V22 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
61 (* case 5: sort, beta (excluded) *)
62 | #K2 #V21 #V22 #W2 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
63 (* case 6: sort, delta (excluded) *)
64 | #K2 #K22 #V21 #V22 #V2 #i2 #_ #_ #_ #H1 #H2 #H3 #H4 destruct
65 (* case 7: sort, theta (excluded) *)
66 | #K2 #V2 #V21 #V22 #W21 #W22 #T21 #T22 #_ #_ #_ #_ #H1 #H2 #H3 #H4 destruct
67 (* case 8: sort, zeta (excluded) *)
68 | #K2 #V2 #T21 #T22 #T20 #_ #_ #H1 #H2 #H3 #H4 destruct
69 (* case 9: sort, tau (excluded) *)
70 | #K2 #V2 #T21 #T22 #_ #H1 #H2 #H3 #H4 destruct
73 (* case 10: lref, sort (excluded) broken *)
74 [ #K2 #k2 #H1 #H2 #H3 #H4 destruct
75 (* case 11: lref, sort (excluded) *)
76 | #K2 #i2 #H1 #H2 #H3 #H4 destruct -K1 K2 T i2 //
77 (* case 12: lref, bind (excluded) *)
78 | #K2 #I2 #V21 #V22 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
79 (* case 13: lref, flat (excluded) *)
80 | #K2 #I2 #V21 #V22 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
81 (* case 14: lref, beta (excluded) *)
82 | #K2 #V21 #V22 #W2 #T21 #T22 #_ #_ #H1 #H2 #H3 #H4 destruct
83 (* case 15: lref, delta (excluded) *)
84 | #K2 #K22 #V21 #V22 #V2 #i2 #_ #_ #_ #H1 #H2 #H3 #H4 destruct
85 (* case 16: lref, theta (excluded) *)
86 | #K2 #V2 #V21 #V22 #W21 #W22 #T21 #T22 #_ #_ #_ #_ #H1 #H2 #H3 #H4 destruct
87 (* case 17: lref, zeta (excluded) *)
88 | #K2 #V2 #T21 #T22 #T20 #_ #_ #H1 #H2 #H3 #H4 destruct
89 (* case 18: lref, tau (excluded) *)
90 | #K2 #V2 #T21 #T22 #_ #H1 #H2 #H3 #H4 destruct
92 | #K1 #I1 #V11 #V12 #T11 #T12 #HV112 #HT112 * -K2 U2 T2
93 (* case 19: bind, sort (excluded) broken *)
94 [ #K2 #k2 #H1 #H2 #H3 #H4 destruct
95 (* case 20: bind, lref (excluded) *)
96 | #K2 #i2 #H1 #H2 #H3 #H4 destruct
97 (* case 21: bind, bind *)
98 | #K2 #I2 #V21 #V22 #T21 #T22 #HV212 #HT212 #H1 #H2 #H3 #H4
99 destruct -T K1 K2 I2 V21 T21;
102 theorem pr_conf: ∀L,T,T1,T2. L ⊢ T ⇒ T1 → L ⊢ T ⇒ T2 →
103 ∃∃T0. L ⊢ T1 ⇒ T0 & L ⊢ T2 ⇒ T0.
104 #L #T @(cw_wf_ind … L T) -L T /3 width=12/
107 lemma pr_conf_bind_bind:
108 ∀L,I1,V11,V12,T11,T12,V22,T22. (
109 ∀L1,T1. #L1 + #T1 < #L + (#V11 + #T11 + 1) →
110 ∀T3,T4. L1 ⊢ T1 ⇒ T3 → L1 ⊢ T1 ⇒ T4 →
111 ∃∃T0. L1 ⊢ T3 ⇒ T0 & L1 ⊢ T4 ⇒ T0
113 L ⊢ V11 ⇒ V12 → L. 𝕓{I1} V11 ⊢ T11 ⇒ T12 →
114 L ⊢ V11 ⇒ V22 → L. 𝕓{I1} V11 ⊢ T11 ⇒ T22 →
115 ∃∃T0. L ⊢ 𝕓{I1} V12. T12 ⇒ T0 & L ⊢ 𝕓{I1} V22. T22 ⇒ T0.