#R #HR #L1 #L2 #H @(TC_star_ind … L2 H) -L2
[ /2 width=1 by lpx_sn_refl/
| /3 width=1 by TC_reflexive, lpx_sn_refl/
-| /3 width=5/
+| /3 width=5 by lpx_sn_pair, step/
]
qed-.
lemma lpx_sn_LTC_TC_lpx_sn: ∀R. (∀L. reflexive … (R L)) →
∀L1,L2. lpx_sn (LTC … R) L1 L2 →
TC … (lpx_sn R) L1 L2.
-#R #HR #L1 #L2 #H elim H -L1 -L2 /2 width=1/
-/2 width=1 by TC_lpx_sn_pair/
+#R #HR #L1 #L2 #H elim H -L1 -L2
+/2 width=1 by TC_lpx_sn_pair, lpx_sn_atom, inj/
qed-.
(* Inversion lemmas on transitive closure ***********************************)
lemma TC_lpx_sn_inv_atom2: ∀R,L1. TC … (lpx_sn R) L1 (⋆) → L1 = ⋆.
#R #L1 #H @(TC_ind_dx … L1 H) -L1
-[ #L1 #H lapply (lpx_sn_inv_atom2 … H) -H //
-| #L1 #L #HL1 #_ #IHL2 destruct
- lapply (lpx_sn_inv_atom2 … HL1) -HL1 //
+[ /2 width=2 by lpx_sn_inv_atom2/
+| #L1 #L #HL1 #_ #IHL2 destruct /2 width=2 by lpx_sn_inv_atom2/
]
qed-.
∀I,L1,K2,V2. TC … (lpx_sn R) L1 (K2.ⓑ{I}V2) →
∃∃K1,V1. TC … (lpx_sn R) K1 K2 & LTC … R K1 V1 V2 & L1 = K1. ⓑ{I} V1.
#R #HR #I #L1 #K2 #V2 #H @(TC_ind_dx … L1 H) -L1
-[ #L1 #H elim (lpx_sn_inv_pair2 … H) -H /3 width=5/
+[ #L1 #H elim (lpx_sn_inv_pair2 … H) -H /3 width=5 by inj, ex3_2_intro/
| #L1 #L #HL1 #_ * #K #V #HK2 #HV2 #H destruct
elim (lpx_sn_inv_pair2 … HL1) -HL1 #K1 #V1 #HK1 #HV1 #H destruct
- lapply (HR … HV2 … HK1) -HR -HV2 #HV2 /3 width=5/
+ lapply (HR … HV2 … HK1) -HR -HV2 /3 width=5 by TC_strap, ex3_2_intro/
]
qed-.
[ #X #H >(TC_lpx_sn_inv_atom2 … H) -X //
| #L2 #I #V2 #IHL2 #X #H
elim (TC_lpx_sn_inv_pair2 … H) // -H -HR
- #L1 #V1 #HL12 #HV12 #H destruct /3 width=1/
+ #L1 #V1 #HL12 #HV12 #H destruct /3 width=1 by/
]
qed-.
lemma TC_lpx_sn_inv_atom1: ∀R,L2. TC … (lpx_sn R) (⋆) L2 → L2 = ⋆.
#R #L2 #H elim H -L2
-[ #L2 #H lapply (lpx_sn_inv_atom1 … H) -H //
-| #L #L2 #_ #HL2 #IHL1 destruct
- lapply (lpx_sn_inv_atom1 … HL2) -HL2 //
+[ /2 width=2 by lpx_sn_inv_atom1/
+| #L #L2 #_ #HL2 #IHL1 destruct /2 width=2 by lpx_sn_inv_atom1/
]
qed-.
∃∃K2,V2. TC … (lpx_sn R) K1 K2 & LTC … R K1 V1 V2 & L2 = K2. ⓑ{I} V2.
#R #HR #L1 #L2 #H @(TC_lpx_sn_ind … H) // -HR -L1 -L2
[ #J #K #W #H destruct
-| #I #L1 #L2 #V1 #V2 #HL12 #HV12 #_ #J #K #W #H destruct /2 width=5/
+| #I #L1 #L2 #V1 #V2 #HL12 #HV12 #_ #J #K #W #H destruct /2 width=5 by ex3_2_intro/
]
qed-.
lemma TC_lpx_sn_inv_lpx_sn_LTC: ∀R. s_rs_trans … R (lpx_sn R) →
∀L1,L2. TC … (lpx_sn R) L1 L2 →
lpx_sn (LTC … R) L1 L2.
-#R #HR #L1 #L2 #H @(TC_lpx_sn_ind … H) // -HR -L1 -L2 /2 width=1/
-qed-.
+/3 width=4 by TC_lpx_sn_ind, lpx_sn_pair/ qed-.
(* Forward lemmas on transitive closure *************************************)