proposition: Theorem ps_mul_0_r : ∀ ps, (ps * 0 = 0)%ps.
proof: Proof. intros ps. rewrite ps_mul_comm. apply ps_mul_0_l. Qed.
imports: Utf8 QArith NPeano Misc NbarM Field2 Fsummation Power_series Puiseux_series Ps_add Ps_add_compat