Birkhoff billiards: only the ellipse has no gaps

About this app

Billiards in a convex table: for the ellipse, every orbit near the rim envelops a smooth caustic and the phase portrait is layered without gaps near the rim. Deform the table with Fourier waves and island chains and chaotic zones tear open between the curves; the Collar panel measures which orbits become wide. Near-boundary Birkhoff conjecture, openai/math family 147.

Subject: Open problems, solved by AI

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