Definition iter_free n x a b c d e :=
iter_rp _ n (do_free x a b c d) (More _ e).

Lemma iter_free_c n x a b c d e :
{v[x]} = {k[a]} .* {v[b]} + {k[c]} .* {v[d]} :> vect K ->
{e[rp_val _ (iter_free n x a b c d e)]} = {e[e]}.