elim ProcS; elim ProcR.
elim EXPH4.
elim LmerSn.
elim LmerK.
elim LmerL.
elim LmerRn.
elim CommLRn.
elim CommKL.
elim CommKRn.
elim CommSnK.
elim CommSnL.
elim CommSnRn.
repeat elim A6.
elim
(A6
(D +
(fun d : D =>
seq (ia D r1 d)
(enc H
(mer (seq (Sn_d d e0) (seq (Sn e1) (S i)))
(mer (K i) (mer (L i) (seq (Rn e1) (seq (Rn e0) (R i)))))))))).
unfold X1 in |- *.
pattern (R i) at 1 in |- *.
elim ProcR.
apply refl_equal.
Qed.

Theorem Lem2 : D + (fun d : D => seq (ia D r1 d) (Y1 d)) = Y.
unfold Y in |- *.