English

Quiver representations arising from degenerations of linear series, II

Algebraic Geometry 2025-12-30 v4

Abstract

We describe all the schematic limits of families of divisors associated to a given family of rank-rr linear series on a one-dimensional family of projective varieties degenerating to a connected reduced projective scheme XX defined over any field, under the assumption that the total space of the family is regular along XX. More precisely, the degenerating family gives rise to a special quiver QQ, called a \emph{Zn\mathbb{Z}^n-quiver}, a special representation L\mathfrak L of QQ in the category of line bundles over XX, called a \emph{maximal exact linked net}, and a special subrepresentation V\mathfrak V of the representation H0(X,L)H^0(X,\mathfrak L) induced from L\mathfrak L by taking global sections, called a \emph{pure exact finitely generated linked net} of dimension r+1r+1. Given g=(Q,L,V)\mathfrak g=(Q,\mathfrak L,\mathfrak V) satisfying these properties, we prove that the quiver Grassmanian LP(V)\mathbb{LP}(\mathfrak{V}) of subrepresentations of V\mathfrak{V} of pure dimension 1, called a \emph{linked projective space}, is local complete intersection, reduced and of pure dimension rr. Furthermore, we prove that there is a morphism LP(V)HilbX\mathbb{LP}(\mathfrak{V})\to\text{Hilb}_X, and that its image parameterizes all the schematic limits of divisors along the degenerating family of linear series if g\mathfrak g arises from one.

Keywords

Cite

@article{arxiv.2112.00514,
  title  = {Quiver representations arising from degenerations of linear series, II},
  author = {Eduardo Esteves and Renan Santos and Eduardo Vital},
  journal= {arXiv preprint arXiv:2112.00514},
  year   = {2025}
}

Comments

36 pages