proposition: Lemma derivable_cst (x : V) : derivable (fun=> x) 0 (1 : R).
proof: Proof. exact/diff_derivable. 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