{ "id": "2301.01121", "version": "v1", "published": "2023-01-03T14:36:56.000Z", "updated": "2023-01-03T14:36:56.000Z", "title": "The Euler characteristic of the moduli space of graphs", "authors": [ "Michael Borinsky", "Karen Vogtmann" ], "comment": "40 pages", "categories": [ "math.AT", "math-ph", "math.GR", "math.MP" ], "abstract": "The moduli space of rank $n$ graphs, the outer automorphism group of the free group of rank $n$ and Kontsevich's Lie graph complex have the same rational cohomology. We show that the associated Euler characteristic grows like $-e^{-1/4}\\,(n/e)^n/(n\\log n)^2$ as $n$ goes to infinity, and thereby prove that the total dimension of this cohomology grows rapidly with $n$.", "revisions": [ { "version": "v1", "updated": "2023-01-03T14:36:56.000Z" } ], "analyses": { "subjects": [ "18G85", "20F65", "20F28", "14T99", "20J06" ], "keywords": [ "moduli space", "kontsevichs lie graph complex", "outer automorphism group", "associated euler characteristic grows", "free group" ], "note": { "typesetting": "TeX", "pages": 40, "language": "en", "license": "arXiv", "status": "editable" } } }