Module Argument.
Notation "t ⊍ u" := (mset_term_plus t u) (at level 40).
Notation "'h' t" := (mset_term_h t) (at level 38).
Notation "•0" := mset_term_zero.
Coercion mset_term_var : nat >-> mset_term.
Fixpoint tower m n :=
match n with
| 0 => []
| S n => (tower m n) ++ (tower m n) ++ (tower m n) ++ (tower m n) ++ [m*n]
end.

Lemma unify_spec {A m n} : A ++ (map (fun i => 2 * i) (seq 0 m)) ≡ (seq 0 n) ++ map S A ->
n = m.