#K1 #K2 #n #_ * #H1 #H2 >length_bind /3 width=1 by minus_Sn_m, conj/
qed-.
+lemma lveq_length_fwd_sn: ∀L1,L2,n1,n2. L1 ≋ⓧ*[n1, n2] L2 → |L1| ≤ |L2| → 0 = n1.
+#L1 #L2 #n1 #n2 #H #HL
+elim (lveq_fwd_length … H) -H
+>(eq_minus_O … HL) //
+qed-.
+
+lemma lveq_length_fwd_dx: ∀L1,L2,n1,n2. L1 ≋ⓧ*[n1, n2] L2 → |L2| ≤ |L1| → 0 = n2.
+#L1 #L2 #n1 #n2 #H #HL
+elim (lveq_fwd_length … H) -H
+>(eq_minus_O … HL) //
+qed-.
+
lemma lveq_inj_length: ∀L1,L2,n1,n2. L1 ≋ⓧ*[n1, n2] L2 →
|L1| = |L2| → ∧∧ 0 = n1 & 0 = n2.
#L1 #L2 #n1 #n2 #H #HL
(* Inversion lemmas with length for local environments **********************)
lemma lveq_inv_void_dx_length: ∀L1,L2,n1,n2. L1 ≋ⓧ*[n1, n2] L2.ⓧ → |L1| ≤ |L2| →
- â\88\83â\88\83m2. L1 â\89\8b â\93§*[n1, m2] L2 & 0 = n1 & ⫯m2 = n2.
+ â\88\83â\88\83m2. L1 â\89\8b â\93§*[n1, m2] L2 & 0 = n1 & â\86\91m2 = n2.
#L1 #L2 #n1 #n2 #H #HL12
lapply (lveq_fwd_length_plus … H) normalize >plus_n_Sm #H0
lapply (plus2_inv_le_sn … H0 HL12) -H0 -HL12 #H0
qed-.
lemma lveq_inv_void_sn_length: ∀L1,L2,n1,n2. L1.ⓧ ≋ⓧ*[n1, n2] L2 → |L2| ≤ |L1| →
- â\88\83â\88\83m1. L1 â\89\8b â\93§*[m1, n2] L2 & ⫯m1 = n1 & 0 = n2.
+ â\88\83â\88\83m1. L1 â\89\8b â\93§*[m1, n2] L2 & â\86\91m1 = n1 & 0 = n2.
#L1 #L2 #n1 #n2 #H #HL
lapply (lveq_sym … H) -H #H
elim (lveq_inv_void_dx_length … H HL) -H -HL