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Examples of Anosov flows with genus one Birkhoff sections

Chi Cheuk Tsang

Abstract

We show that a transitive Anosov flow with orientable stable and unstable foliations that either (i) admits a Birkhoff section whose first return map is a Penner type pseudo-Anosov map, or (ii) is totally periodic admits a genus one Birkhoff section. This provides evidence for a conjecture of Fried and Ghys. The proof utilizes a result of the author on the horizontal Goodman surgery operation. To apply this result for showing (i), we establish correspondence between horizontal Goodman surgery on pseudo-Anosov flows and horizontal surgery on veering triangulations in the layered setting.

Examples of Anosov flows with genus one Birkhoff sections

Abstract

We show that a transitive Anosov flow with orientable stable and unstable foliations that either (i) admits a Birkhoff section whose first return map is a Penner type pseudo-Anosov map, or (ii) is totally periodic admits a genus one Birkhoff section. This provides evidence for a conjecture of Fried and Ghys. The proof utilizes a result of the author on the horizontal Goodman surgery operation. To apply this result for showing (i), we establish correspondence between horizontal Goodman surgery on pseudo-Anosov flows and horizontal surgery on veering triangulations in the layered setting.
Paper Structure (42 sections, 51 theorems, 10 equations, 53 figures)

This paper contains 42 sections, 51 theorems, 10 equations, 53 figures.

Key Result

Theorem 1.2

Let $\phi^t$ be the geodesic flow of a negatively curved orbifold. Then $\phi^t$ admits a genus one Birkhoff section.

Figures (53)

  • Figure 1: Left: A local picture of an Anosov flow. Right: A local picture of its orbit space.
  • Figure 2: Given an Anosov-type fully-punctured pseudo-Anosov map $f:S^\circ \to S^\circ$, we can construct an Anosov flow by collapsing the extension $\overline{\phi}^t_f$ of the suspension flow along boundary tori. The image of $S^\circ$ becomes the interior of a Birkhoff section.
  • Figure 3: A local picture of a pseudo-Anosov flow near a singular orbit.
  • Figure 4: A local example of a positive curve (in red) and a negative curve (blue), projected along the flow direction onto a plane.
  • Figure 5: Left/right: Local form of a positive/negative surgery curve, respectively.
  • ...and 48 more figures

Theorems & Definitions (112)

  • Conjecture 1.1: Fried, Ghys
  • Theorem 1.2: Dehornoy-Shannon DS19
  • Theorem 1.3
  • Theorem 1.4
  • Theorem 1.5: Tsa24
  • Theorem 1.6
  • Definition 2.1
  • Definition 2.2
  • Definition 2.3
  • Definition 2.4
  • ...and 102 more