English

Infinite staircases for Hirzebruch surfaces

Symplectic Geometry 2021-04-21 v2

Abstract

We consider the embedding capacity functions cHb(z)c_{H_b}(z) for symplectic embeddings of ellipsoids of eccentricity zz into the family of nontrivial rational Hirzebruch surfaces HbH_b with symplectic form parametrized by b[0,1)b\in [0,1). This function was known to have an infinite staircase in the monotone cases (b=0b= 0 and b=1/3 b= 1/3). It is also known that for each bb there is at most one value of zz that can be the accumulation point of such a staircase. In this manuscript, we identify three sequences of open, disjoint, blocked bb-intervals, consisting of bb-parameters where the embedding capacity function for HbH_b does not contain an infinite staircase. There is one sequence in each of the intervals (0,1/5)(0,1/5), (1/5,1/3)(1/5,1/3), and (1/3,1)(1/3,1). We then establish six sequences of associated infinite staircases, one occurring at each endpoint of the blocked bb-intervals. The staircase numerics are variants of those in the Fibonacci staircase for the projective plane (the case b=0b=0). We also show that there is no staircase at the point b=1/5b=1/5, even though this value is not blocked. The focus of this paper is to develop techniques, both graphical and numeric, that allow identification of potential staircases, and then to understand the obstructions well enough to prove that the purported staircases really do have the required properties. A subsequent paper will explore in more depth the set of bb that admit infinite staircases.

Cite

@article{arxiv.2010.08567,
  title  = {Infinite staircases for Hirzebruch surfaces},
  author = {Maria Bertozzi and Tara S. Holm and Emily Maw and Dusa McDuff and Grace T. Mwakyoma and Ana Rita Pires and Morgan Weiler},
  journal= {arXiv preprint arXiv:2010.08567},
  year   = {2021}
}

Comments

90 pages, 12 figures. Version 2 has several typos fixed and numbering changed to match style in to-be-published version

R2 v1 2026-06-23T19:24:42.117Z