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Weak mixing of irrational triangular billiards
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Weak mixing of triangular billiards with an irrational angle. Proves that the billiard flow in every nondegenerate Euclidean triangle with at least one angle irrational relative to π is weakly mixing for normalized area times uniform direction. This strengthens ergodicity on the entire irrational-angle class, with no genericity or Diophantine restrictions.

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released 2026-10-05  |  1 theorem · 4 lemmas · 7 proofs · 5,749 words  |  PLAY LEVEL 1 »  (pdf)
We prove that the unit-speed billiard flow in every nondegenerate Euclidean triangle with at least one angle irrational relative to π is weakly mixing for normalized Liouville measure. Equivalently, the product of the flow with itself is ergodic.
released 2026-09-25  |  1 theorem · 3 lemmas · 6 proofs · 5,033 words  |  PLAY LEVEL 2 »  (pdf)
We prove that the unit-speed billiard flow in every nondegenerate Euclidean triangle with at least one angle irrational relative to π is ergodic for normalized area times uniform angular measure. No genericity or Diophantine condition is required. The flow is considered outside the null set of trajectories that hit a vertex.

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