intros.
elim (EXPH4 (K i)).
elim LmerK.
elim LmerL.
elim Lmers5.
elim LmerTnd.
elim CommTn_dL.
elim CommTn_ds5.
elim CommLs5.
elim CommKs5.
elim CommKL.
elim CommTn_dK.
repeat elim A6.
repeat elim A6'.
apply refl_equal.
Qed.

Theorem Lem19 :
forall d : D,
alt
(seq (ia one int i)
(enc H
(mer (seq (ia frame s6 (tuple e0)) (L i))
(mer (seq (Rn e0) (R i)) (mer (K i) (seq (Tn_d d e1) (S i)))))))
(seq (ia one int i)
(enc H
(mer (seq (ia frame s6 sce) (L i))
(mer (seq (Rn e0) (R i)) (mer (K i) (seq (Tn_d d e1) (S i))))))) =
enc H
(mer (seq (Rn e0) (R i))
(mer
(alt (seq (ia one int i) (seq (ia frame s6 (tuple e0)) (L i)))
(seq (ia one int i) (seq (ia frame s6 sce) (L i))))
(mer (K i) (seq (Tn_d d e1) (S i))))).