English

General Kontsevich-style formula for Hirzebruch Surfaces

Algebraic Geometry 2025-08-21 v1 Combinatorics

Abstract

Tyomkin's correspondence theorem states the equality of counts of rational curves of fixed homology class in a toric surface satisfying point and cross-ratio conditions with their tropical counterparts. Such correspondence theorems allow us to derive non-tropical results from tropical ones; for example, Mikhalkin's correspondence theorem is used in the tropical proof of the famous Kontsevich formula for counts of plane rational curves of degree dd satisfying point conditions. This formula has been generalized to counts of curves in the Hirzebruch surface F2\mathbb{F}_{2} satisfying point conditions. Further generalizations allow curves in P2\mathbb{P}^2 to satisfy multiple cross-ratio conditions. In this paper, we present a Kontsevich-style formula for the Hirzebruch surface Fr\mathbb{F}_r, rNr \in \mathbb{N}, which counts rational tropical curves of a fixed homology class satisfying point and multiple cross-ratio conditions using tropical methods. Moreover, the cross-ratio conditions we impose on the curves allow more freedom.

Keywords

Cite

@article{arxiv.2508.14206,
  title  = {General Kontsevich-style formula for Hirzebruch Surfaces},
  author = {Parisa Ebrahimian},
  journal= {arXiv preprint arXiv:2508.14206},
  year   = {2025}
}

Comments

58 pages, 41 figures