A Birman-Series type result for geodesics with infinitely many self-intersections

TL;DR

This paper extends the Birman-Series theorem to sets of hyperbolic surface geodesics with controlled self-intersection growth, showing they are contained in nowhere dense sets with Hausdorff dimension 1.

Contribution

It introduces a self-intersection function for geodesics and generalizes the Birman-Series result to geodesics with subquadratic self-intersection growth.

Findings

Geodesics with self-intersection functions in o(l^2) are contained in nowhere dense sets.

The Hausdorff dimension of these sets remains 1.

The result broadens understanding of geodesic complexity on hyperbolic surfaces.

Abstract

Given a hyperbolic surface $\S$, a classic result of Birman and Series states that for each $K$, all complete geodesics with at most $K$ self-intersections can only pass through a certain nowhere dense, Hausdorff dimension 1 subset of $\S$. We define a self-intersection function for each complete geodesic, which bounds the number of self-intersections in finite length subarcs. We then extend the Birman-Series result to sets of complete geodesics with certain bounds on their self-intersection functions. In fact, we get the same conclusion as the Birman-Series result for sets of complete geodesics whose self-intersection functions are in $o(l^2)$, where $l$ measures arclength.