English

Length minimization of filling pairs on hyperbolic surfaces

Geometric Topology 2026-01-23 v1 Metric Geometry

Abstract

A filling pair (α,β)(\alpha, \beta) of a surface SgS_g is a pair of simple closed curves in minimal position such that the complement of αβ\alpha\cup\beta in SgS_g is a disjoint union of topological disks. A filling pair is said to be minimally intersecting if the number of intersections between them, or equivalently, the number of complementary disks, is minimal among all filling pairs of SgS_g. For surfaces of genus g3g \geq 3, minimal filling pairs are well understood, whereas in genus two, such a pair divides the surface into exactly two disks. In this paper, we classify all minimal filling pairs up to the action of the mapping class group in genus two and determine the length of the shortest minimal filling pair.

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Cite

@article{arxiv.2601.15524,
  title  = {Length minimization of filling pairs on hyperbolic surfaces},
  author = {Ni An and Bhola Nath Saha and Bidyut Sanki},
  journal= {arXiv preprint arXiv:2601.15524},
  year   = {2026}
}

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23 pages