proposition: Lemma r_of_p1 p : [r_of p, 1%:pr] = p.
proof: Proof. by apply/val_inj; rewrite /= r_of_pqE s_of_p1 invr1 mulr1. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum) mathcomp(reals normedtype) mathcomp(mathcomp_extra boolp) mathcomp(lra ring Rstruct)