Source authenticated

Bang's half-area cylinder covering question (and the 1-codimensional cylinder covering conjecture)

Theorem 1.1: a regular tetrahedron KK with Amin⁡(K)=2A_{\min}(K)=\sqrt2 has, for each 0<ε≤1/20000<\varepsilon\le1/2000, a cover by 2⌈2/ε2⌉2\lceil2/\varepsilon^2\rceil cylinders with compact triangular perpendicular bases and 12∑∣Bi∣=12−136000ε2+O(ε4)\frac1{\sqrt2}\sum|B_i|=\frac12-\frac{13}{6000}\varepsilon^2+O(\varepsilon^4), strictly below half. Corollary 1.2: every nondegenerate tetrahedron has a finite cover with directionwise relative cost below 1/2, refuting the Bezdek-Khan conjecture. Not shown: the optimal constant (Bezdek-Litvak's lower bound 1/3 stands) or counterexamples among centrally symmetric bodies.

Exact FrontierDelta

Prior state unknown→disproved

Scope and record

Occurred: Sep 27, 2026

Delta type: SOURCE CLAIM

Assumptions: VibeMathed verification: lean-checked. Publication: announcement. AI contribution: ai-discovered. VibeMathed editorial classifications, scores, notes, relations, and dataset structure are CC BY 4.0. Source statements and linked content retain their own rights.

Canonical aliases: Bang's half-area cylinder covering question (and the 1-codimensional cylinder covering conjecture) · Half-area cylinder covering conjecture

Confidence: Not scored

Registry verification: lean checked · announcement · candidate

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Attribution

VibeMathed
registry · event recorded by

Unreleased internal OpenAI model
model · ai model contributor · OpenAI

Artifacts and verifiers

Lean formalization: TriangularCovering/Main.lean

lean artifact · pending

Artifact ↗
Lean formalization: CylinderCovering/Main.lean (four-paper aggregate)

lean artifact · pending

Artifact ↗

Compute record

No linked compute attempts recorded.

Lineage and corrections

Lean formalization: CylinderCovering/Main.lean (four-paper aggregate) evidence for this event

This event attributed to Unreleased internal OpenAI model

Bang's half-area cylinder covering question (and the 1-codimensional cylinder covering conjecture) parent of this event

Theorem 1.1: a regular tetrahedron KK with Amin⁡(K)=2A_{\min}(K)=\sqrt2 has, for each 0<ε≤1/20000<\varepsilon\le1/2000, a cover by 2⌈2/ε2⌉2\lceil2/\varepsilon^2\rceil cylinders with compact triangular perpendicular bases and 12∑∣Bi∣=12−136000ε2+O(ε4)\frac1{\sqrt2}\sum|B_i|=\frac12-\frac{13}{6000}\varepsilon^2+O(\varepsilon^4), strictly below half. Corollary 1.2: every nondegenerate tetrahedron has a finite cover with directionwise relative cost below 1/2, refuting the Bezdek-Khan conjecture. Not shown: the optimal constant (Bezdek-Litvak's lower bound 1/3 stands) or counterexamples among centrally symmetric bodies. parent of this event

Bezdek-Khan, The geometry of homothetic covering and illumination (Conjecture 4.13) evidence for this event

Companion: Finite cylinder approximation of ruled sets evidence for this event

VibeMathed record: Bang's half-area cylinder covering question (and the 1-codimensional cylinder covering conjecture) evidence for this event

Companion: Slope-field perturbations of the two-cylinder covering evidence for this event

Lean formalization: TriangularCovering/Main.lean evidence for this event

Companion: Finite triangular approximation of radial sweeps evidence for this event

Bang's half-area cylinder covering question (and the 1-codimensional cylinder covering conjecture) evidence for this event

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