{ "id": "1711.04762", "version": "v1", "published": "2017-11-13T18:58:42.000Z", "updated": "2017-11-13T18:58:42.000Z", "title": "Calculating the homology and intersection form of a 4-manifold from a trisection diagram", "authors": [ "Peter Feller", "Michael Klug", "Trent Schirmer", "Drew Zemke" ], "comment": "14 pages, 2 figures. Submitted to appear as part of the Proceedings of the National Academy of Sciences collection on trisections of 4-manifolds", "categories": [ "math.GT" ], "abstract": "Given a diagram for a trisection of a 4-manifold $X$, we describe the homology and the intersection form of $X$ in terms of the three subgroups of $H_1(F;\\mathbb{Z})$ generated by the three sets of curves and the intersection pairing on $H_1(F;\\mathbb{Z})$. This includes explicit formulas for the second and third homology groups of $X$ as well an algorithm to compute the intersection form. Moreover, we show that all $(g;k,0,0)$-trisections admit \"algebraically trivial\" diagrams.", "revisions": [ { "version": "v1", "updated": "2017-11-13T18:58:42.000Z" } ], "analyses": { "keywords": [ "intersection form", "trisection diagram", "third homology groups", "explicit formulas", "calculating" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }