English

A combinatorial approach to scattering diagrams

Combinatorics 2026-05-21 v3 Algebraic Geometry Representation Theory

Abstract

Scattering diagrams arose in the context of mirror symmetry, but a special class of scattering diagrams (the cluster scattering diagrams) were recently developed to prove key structural results on cluster algebras. We use the connection to cluster algebras to calculate the function attached to the limiting wall of a rank-2 cluster scattering diagram of affine type. In the skew-symmetric rank-2 affine case, this recovers a formula due to Reineke. In the same case, we show that the generating function for signed Narayana numbers appears in a role analogous to a cluster variable. In acyclic finite type, we construct cluster scattering diagrams of acyclic finite type from Cambrian fans and sortable elements, with a simple direct proof.

Keywords

Cite

@article{arxiv.1806.05094,
  title  = {A combinatorial approach to scattering diagrams},
  author = {Nathan Reading},
  journal= {arXiv preprint arXiv:1806.05094},
  year   = {2026}
}

Comments

The second half of arXiv:1712.06968, which was originally "Scattering diagrams and scattering fans". The contents of this paper will be removed from arXiv:1712.06968, which will be re-titled "Scattering fans." Version 2: Minor expository changes. (We thank some anonymous referees for helpful comments.) Version 3: Corrections to reconcile the arXiv version with the final pre-publication version

R2 v1 2026-06-23T02:28:50.290Z