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Recurrence and Embeddings in Planar Wind-Tree Models

Chen Frenkel

Abstract

We study periodic infinite billiards in the plane. We show that for rational models, some particular obstacles can be added periodically, so that the billiard flow in the resulting table is recurrent in almost every direction.

Recurrence and Embeddings in Planar Wind-Tree Models

Abstract

We study periodic infinite billiards in the plane. We show that for rational models, some particular obstacles can be added periodically, so that the billiard flow in the resulting table is recurrent in almost every direction.
Paper Structure (41 sections, 16 theorems, 17 equations, 6 figures)

This paper contains 41 sections, 16 theorems, 17 equations, 6 figures.

Key Result

Theorem 1.1

For any rational wind-tree model $\mathrm{WT}(\Lambda, \Omega)$ one can add obstacles to $\Omega$ so that for the new configuration $\widehat{\Omega}$ the billiard flow in $\mathrm{WT}(\Lambda, \widehat{\Omega})$ is recurrent.

Figures (6)

  • Figure 1: The original wind-tree model.
  • Figure 2: $\mathrm{WT}(\Lambda, \Omega)$ (top) and $\mathrm{WT}(\Lambda, \widehat{\Omega})$ (bottom).
  • Figure 3: A $\mathbb{Z}$-cover defined by a cycle on the torus.
  • Figure 4: An example of $X$ for $\Omega$ consisting of a triangle with angles $\frac{\pi}{2},\frac{3\pi}{8},\frac{\pi}{8}$.
  • Figure 5: Example for the cover cycles.
  • ...and 1 more figures

Theorems & Definitions (22)

  • Theorem 1.1
  • Definition 2.1
  • Definition 2.3
  • Corollary 2.4
  • Theorem 2.5
  • Theorem 2.6
  • Theorem 2.7
  • Theorem 2.8: KMS
  • Theorem 2.9
  • Theorem 2.10: CE
  • ...and 12 more