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15 include "basic_2/substitution/cpys_cny.ma".
16 include "basic_2/substitution/cpys_cpys.ma".
17 include "basic_2/substitution/cpye.ma".
19 (* EVALUATION FOR CONTEXT-SENSITIVE EXTENDED SUBSTITUTION ON TERMS **********)
21 (* Advanced properties ******************************************************)
23 lemma cpye_cpys_conf: ∀G,L,T,T2,d,e. ⦃G, L⦄ ⊢ T ▶*[d, e] 𝐍⦃T2⦄ →
24 ∀T1. ⦃G, L⦄ ⊢ T ▶*[d, e] T1 → ⦃G, L⦄ ⊢ T1 ▶*[d, e] T2.
25 #G #L #T #T2 #d #e * #H2 #HT2 #T1 #H1 elim (cpys_conf_eq … H1 … H2) -T
26 #T0 #HT10 #HT20 >(cpys_inv_cny1 … HT2 … HT20) -T2 //