English

Wall-crossings for Hassett descendant potentials

Algebraic Geometry 2019-07-16 v1 Combinatorics

Abstract

This paper solves the combinatorics relating the intersection theory of ψ\psi-classes of Hassett spaces to that of Mg,n\overline{\mathcal{M}}_{g,n}. A generating function for intersection numbers of ψ\psi classes on all Hassett spaces is obtained from the Gromov-Witten potential of a point via a non-invertible transformation of variables. When restricting to diagonal weights, the changes of variables are invertible and explicitly described as polynomial functions. Finally, the comparison of potentials is extended to the level of cycles: the pinwheel cycle potential, a generating function for tautological classes of rational tail type on Mg,n\overline{\mathcal{M}}_{g,n} is the right instrument to describe the pull-back to Mg,n\overline{\mathcal{M}}_{g,n} of all monomials of ψ\psi classes on Hassett spaces.

Keywords

Cite

@article{arxiv.1907.06277,
  title  = {Wall-crossings for Hassett descendant potentials},
  author = {Vance Blankers and Renzo Cavalieri},
  journal= {arXiv preprint arXiv:1907.06277},
  year   = {2019}
}