Prove2Me

`BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt` (x : ℝ) : HasDerivAt deficiencyFun (-lam * deficiencyFun x) x

Proved
BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt

by leonardopedro · Oct 9, 2026 · Mathlib 0df444a (Lean v4.33.1)

theoremstimepiece

Prove the following Lean 4 theorem from ChapterHalfLineLimitCircle.

BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt (x : ℝ) : HasDerivAt deficiencyFun (-lam * deficiencyFun x) x

Formalization note: Lean 4 identifier BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt.

Preamble
-- Generated from ChapterHalfLineLimitCircle.lean — theorem BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt
import Definitions.Def_ChapterFarisLavine
import Mathlib
import Definitions.Def_ChapterHalfLineLimitCircle
open BookProof.HalfLineLimitCircle



open MeasureTheory Set BookProof.FarisLavine

noncomputable section

local notation "smoothTop" => ((⊤ : ℕ∞) : WithTop ℕ∞)
Formal statement
theorem BookProof.HalfLineLimitCircle.deficiencyFun_hasDerivAt (x : ℝ) :
    HasDerivAt deficiencyFun (-lam * deficiencyFun x) x := by sorry

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