From fb6b323140c1a34fbcae64eca06ea595f72952f3 Mon Sep 17 00:00:00 2001 From: KM-Cloud Date: Fri, 8 May 2026 09:18:02 -0700 Subject: [PATCH 1/2] feat(ErdosProblems/114): add finite certificate variant --- FormalConjectures/ErdosProblems/114.lean | 97 ++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 FormalConjectures/ErdosProblems/114.lean diff --git a/FormalConjectures/ErdosProblems/114.lean b/FormalConjectures/ErdosProblems/114.lean new file mode 100644 index 000000000..18e715298 --- /dev/null +++ b/FormalConjectures/ErdosProblems/114.lean @@ -0,0 +1,97 @@ +/- +Copyright 2026 The Formal Conjectures Authors. + +Licensed under the Apache License, Version 2.0 (the "License"); +you may not use this file except in compliance with the License. +You may obtain a copy of the License at + + https://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, software +distributed under the License is distributed on an "AS IS" BASIS, +WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +See the License for the specific language governing permissions and +limitations under the License. +-/ + +import FormalConjectures.Util.ProblemImports + +/-! +# Erdős Problem 114 + +*Reference:* [erdosproblems.com/114](https://www.erdosproblems.com/114) + +The **Erdős--Herzog--Piranian lemniscate-length conjecture** asks whether, +among monic complex polynomials of degree `n`, the lemniscate +`{z : ℂ | ‖p.eval z‖ = 1}` has maximal length for `p = X ^ n - C 1`. + +The all-degree conjecture remains open. The finite statement below records +the current certificate-backed range `1 ≤ n ≤ 14`: degree `1` is elementary, +degree `2` follows from the Eremenko--Hayman treatment, and degrees `3` +through `14` are supported by the Mendoza finite-degree certificate packet. +The Lean statements here do not formalize those external certificates. + +### References + +- [EHP58] Erdős, P., Herzog, F., Piranian, G. (1958). *Metric properties of + polynomials*. J. Analyse Math. 6, 125--148. +- [EH99] Eremenko, A., Hayman, W. (1999). *On the length of lemniscates*. + Michigan Math. J. 46, 409--415. +- [Po61] Pommerenke, Ch. (1961). *Uber die Kapazitat ebener Kontinuen*. + Math. Ann. 144, 115--120. +- [Ta25] Tao, T. (2025). *The Erdős--Herzog--Piranian conjecture for large n*. +- [Me26] Mendoza, K. A. (2026). *Finite-degree verification for the + Erdős--Herzog--Piranian lemniscate-length conjecture*. + doi:10.5281/zenodo.19184467. + Source release: https://github.com/MendozaLab/erdos-experiments/releases/tag/v3.1.0. + +### AI disclosure + +Lean 4 code in this file was drafted with AI assistance. The mathematical +content, external certificate packet, and references are the contributor's +responsibility. +-/ + +open Polynomial MeasureTheory ENNReal Classical + +namespace Erdos114 + +/-- The level-1 lemniscate of a complex polynomial `p`. -/ +def levelCurveUnit (p : ℂ[X]) : Set ℂ := + {z : ℂ | ‖p.eval z‖ = 1} + +/-- The length of a subset of `ℂ`, represented as its one-dimensional +Hausdorff measure. -/ +noncomputable def length (s : Set ℂ) : ℝ≥0∞ := + μH[1] s + +/-- The length of the level-1 lemniscate of `p`. -/ +noncomputable def lemniscateLength (p : ℂ[X]) : ℝ≥0∞ := + length (levelCurveUnit p) + +/-- **Erdős Problem 114** (open conjecture). Among monic complex polynomials +of degree `n`, `X ^ n - C 1` maximizes the length of the level-1 lemniscate. + +This is the all-degree conjecture and remains open. -/ +@[category research open, AMS 30] +theorem erdos_114 (n : ℕ) (hn : 1 ≤ n) + (p : ℂ[X]) (hp : p.Monic) (hp_deg : p.natDegree = n) : + lemniscateLength p ≤ lemniscateLength (X ^ n - C (1 : ℂ)) := by + sorry + +/-- **Finite-degree EHP certificate range.** For `1 ≤ n ≤ 14`, the polynomial +`X ^ n - C 1` maximizes the length of the level-1 lemniscate among monic +complex polynomials of exact degree `n`. + +This statement records a finite, externally certificate-backed result: `n = 1` +is elementary, `n = 2` follows from the Eremenko--Hayman treatment, and +`3 ≤ n ≤ 14` is supported by the Mendoza 2026 IEEE-1788 interval certificate +packet. The external certificate pipeline is not formalized in this Lean file, +so the proof remains a `sorry` rather than an imported axiom. -/ +@[category research solved, AMS 30] +theorem erdos_114_finite_le_14 (n : ℕ) (hn : 1 ≤ n) (hn14 : n ≤ 14) + (p : ℂ[X]) (hp : p.Monic) (hp_deg : p.natDegree = n) : + lemniscateLength p ≤ lemniscateLength (X ^ n - C (1 : ℂ)) := by + sorry + +end Erdos114 From 713d3fae5fe778030d0c661ff25c493fdb434fe9 Mon Sep 17 00:00:00 2001 From: KM-Cloud Date: Fri, 8 May 2026 10:27:48 -0700 Subject: [PATCH 2/2] docs(ErdosProblems/114): pin v3.1.0 Zenodo DOI --- FormalConjectures/ErdosProblems/114.lean | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/FormalConjectures/ErdosProblems/114.lean b/FormalConjectures/ErdosProblems/114.lean index 18e715298..3d871f528 100644 --- a/FormalConjectures/ErdosProblems/114.lean +++ b/FormalConjectures/ErdosProblems/114.lean @@ -42,7 +42,7 @@ The Lean statements here do not formalize those external certificates. - [Ta25] Tao, T. (2025). *The Erdős--Herzog--Piranian conjecture for large n*. - [Me26] Mendoza, K. A. (2026). *Finite-degree verification for the Erdős--Herzog--Piranian lemniscate-length conjecture*. - doi:10.5281/zenodo.19184467. + Version doi:10.5281/zenodo.20087919; concept doi:10.5281/zenodo.19184467. Source release: https://github.com/MendozaLab/erdos-experiments/releases/tag/v3.1.0. ### AI disclosure