Universal piecewise polynomiality for counting curves in toric surfaces

TL;DR

This paper proves that counting curves in toric surfaces exhibits a universal piecewise polynomial structure and expresses these invariants using bosonic Fock space matrix elements.

Contribution

It establishes the polynomiality of curve counting invariants across general toric surfaces and provides a new matrix element formulation in Fock space.

Findings

Invariants are piecewise polynomial in their entries.

Polynomiality extends to changing between more general toric surfaces.

Invariants can be expressed as matrix elements in bosonic Fock space.

Abstract

Inspired by piecewise polynomiality results of double Hurwitz numbers, Ardila and Brugall\'e introduced an enumerative problem which they call double Gromov--Witten invariants of Hirzebruch surfaces. These invariants serve as a two-dimensional analogue and satisfy a similar piecewise polynomial structure. More precisely, they introduced the enumeration of curves in Hirzebruch surfaces satisfying point conditions and tangency conditions on the two parallel toric boundaries. These conditions are stored in four partitions and the resulting invariants are piecewise polynomial in their entries. Moreover, they found that these expressions also behave polynomially with respect to the parameter determining the underlying Hirzebruch surfaces. Based on work of Ardila and Block, they proposed that such a polynomiality could also hold while changing between more general toric surfaces corresponding to $h$-transverse polygons. In this work, we answer this question affirmatively. Moreover, we express the resulting invariants for $h$-transverse polygons as matrix elements in the two-dimensional bosonic Fock space.