{ "id": "1712.06968", "version": "v1", "published": "2017-12-19T15:06:53.000Z", "updated": "2017-12-19T15:06:53.000Z", "title": "Scattering diagrams and scattering fans", "authors": [ "Nathan Reading" ], "comment": "58 pages, 7 figures, 5 tables", "categories": [ "math.CO", "math.AG", "math.RT" ], "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. This paper studies scattering diagrams from a combinatorial and discrete-geometric point of view. We show that a consistent scattering diagram with minimal support cuts the ambient space into a complete fan. We give a simple derivation of 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 point out that the generating function for signed Narayana numbers appears in a role analogous to a cluster variable. In acyclic finite type, cluster scattering fans are known to coincide with Cambrian fans because both coincide with the g-vector fan. Here, we construct scattering diagrams of acyclic finite type from Cambrian fans and sortable elements, with a simple direct proof. The paper includes two brief expositions of scattering diagrams, one largely following the conventions of Gross, Hacking, Keel, and Kontsevich, and the other (related by a global transpose) more compatible with the conventions of Fomin and Zelevinsky.", "revisions": [ { "version": "v1", "updated": "2017-12-19T15:06:53.000Z" } ], "analyses": { "subjects": [ "13F60", "14N35", "52C99", "05E10", "05A15" ], "keywords": [ "scattering fans", "acyclic finite type", "cluster scattering diagram", "cambrian fans", "signed narayana numbers appears" ], "note": { "typesetting": "TeX", "pages": 58, "language": "en", "license": "arXiv", "status": "editable" } } }