proposition: Lemma hole_l_varD : forall E k p A, p < k -> E |= p := A -> (initialSeg E k ++ finalSeg E (S k)) |= p := A.
proof: Proof. intros. apply (proj1 (proj1 (equiv_hole_l E H) A)); trivial. Qed.
imports: CoLoR(RelExtras ListExtras TermsLifting LogicUtil OptUtil) Coq(Arith Setoid Morphisms Lia)