intros a b; case a; case b; simpl in |- *; auto.
intros a0 m a1 m0; split; auto.
apply mult_mon_com.
Qed.

Theorem eqTerm_multTerm_comp :
forall a b c d : Term,
eqTerm a b -> eqTerm c d -> eqTerm (multTerm a c) (multTerm b d).