#[deprecated(since="8.19")]
Notation tech_single_z_r_R1 := tech_single_z_r_R1_depr (only parsing).

Lemma Rinv_mult_simpl_depr : forall r1 r2 r3, r1 <> 0 -> r1 * / r2 * (r3 * / r1) = r3 * / r2.