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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
8 (* ||A|| http://helm.cs.unibo.it *)
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15 include "basic_2/relocation/ldrop_append.ma".
16 include "basic_2/reduction/crx.ma".
18 (* CONTEXT-SENSITIVE EXTENDED REDUCIBLE TERMS *******************************)
20 (* Advanved properties ******************************************************)
22 lemma crx_append_sn: ∀h,g,G,L,K,T. ⦃G, L⦄ ⊢ 𝐑[h, g]⦃T⦄ → ⦃G, K @@ L⦄ ⊢ 𝐑[h, g]⦃T⦄.
23 #h #g #G #L #K0 #T #H elim H -L -T /2 width=1/ /2 width=2/
25 lapply (ldrop_fwd_length_lt2 … HLK) #Hi
26 lapply (ldrop_O1_append_sn_le … HLK … K0) -HLK /2 width=2/ -Hi /2 width=4/
29 lemma trx_crx: ∀h,g,G,L,T. ⦃G, ⋆⦄ ⊢ 𝐑[h, g]⦃T⦄ → ⦃G, L⦄ ⊢ 𝐑[h, g]⦃T⦄.
30 #h #g #G #L #T #H lapply (crx_append_sn … H) //