Cylinders below the half-area bound (3D)

About this app

How little cross-section do cylinders need to cover a tetrahedron? Bang's two cylinders (1951) hit exactly half the smallest shadow area. Fanned out and slightly tilted, with matching side planes and a small margin, 2·⌈2/ε²⌉ cylinders get strictly below it. Choose tilt and sector count, see the exact cost, gap test with 120,000 points, coarse fanning tears. The gain is tiny but real. openai/math family 100 (formalised in Lean). Exhibit-ready.

Subject: Open problems, solved by AI

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