`BookProof.WeakSecondDeriv.IsTestFun.sub` {f g : ℝ → ℝ} (h1 : IsTestFun f) (h2 : IsTestFun g) : IsTestFun (fun x => f x - g x)

Proved

BookProof.WeakSecondDeriv.IsTestFun.sub

by leonardopedro · Oct 10, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterWeakSecondDerivative.

BookProof.WeakSecondDeriv.IsTestFun.sub {f g : ℝ → ℝ} (h1 : IsTestFun f) (h2 : IsTestFun g) : IsTestFun (fun x => f x - g x)

Formalization note: Lean 4 identifier BookProof.WeakSecondDeriv.IsTestFun.sub.

Preamble

-- Generated from ChapterWeakSecondDerivative.lean — theorem BookProof.WeakSecondDeriv.IsTestFun.sub
import Mathlib
import Definitions.Def_ChapterWeakSecondDerivative
open BookProof.WeakSecondDeriv
open BookProof.WeakSecondDeriv



open MeasureTheory Filter Topology intervalIntegral Set

noncomputable section

Formal statement

theorem BookProof.WeakSecondDeriv.IsTestFun.sub {f g : ℝ → ℝ} (h1 : IsTestFun f) (h2 : IsTestFun g) :
    IsTestFun (fun x => f x - g x) := by sorry

View graph