proposition: Lemma diff_Rinv (x : R) : x != 0 -> 'd GRing.inv x = (fun h : R => - x ^- 2 *: h) :> (R -> R).
proof: Proof. move=> xn0; have -> : (fun h : R => - x ^- 2 *: h) = ( *:%R (- x ^- 2)) by []. by apply: diff_unique; have [] := dinv xn0. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum matrix interval) mathcomp(mathcomp_extra boolp classical_sets functions) reals signed topology prodnormedzmodule normedtype landau forms