{ "id": "2006.12192", "version": "v1", "published": "2020-06-22T12:43:45.000Z", "updated": "2020-06-22T12:43:45.000Z", "title": "Lifespan estimates for $2$-dimensional semilinear wave equations in asymptotically Euclidean exterior domains", "authors": [ "Ning-An Lai", "Mengyun Liu", "Kyouhei Wakasa", "Chengbo Wang" ], "comment": "24 pages", "categories": [ "math.AP" ], "abstract": "In this paper we study the initial boundary value problem for two-dimensional semilinear wave equations with small data, in asymptotically Euclidean exterior domains. We prove that if $1