proposition: Lemma s_of_p0 p : [s_of p, 0%:pr] = p.
proof: Proof. by apply/val_inj; rewrite /= s_of_pqE onem0 mulr1 onemK. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum) mathcomp(reals normedtype) mathcomp(mathcomp_extra boolp) mathcomp(lra ring Rstruct)