Theorem Lem7 : forall d : D, seq (ia D s4 d) (X2 d) = enc H (mer (K i) (mer (seq (ia D s4 d) (seq (ia frame s5 (tuple e0)) (seq (Rn e0) (R i)))) (mer (seq (Tn_d d e0) (seq (Sn e1) (S i))) (L i)))).