{ "id": "2403.15298", "version": "v1", "published": "2024-03-22T15:45:09.000Z", "updated": "2024-03-22T15:45:09.000Z", "title": "On the matching complexes of categorical product of path graphs", "authors": [ "Raju Kumar Gupta", "Sourav Sarkar", "Sagar S. Sawant", "Samir Shukla" ], "comment": "36 pages, 33 figures, comments are welcome", "categories": [ "math.CO" ], "abstract": "The matching complex $\\mathsf{M}(G)$ of a graph $G$ is a simplicial complex whose simplices are matchings in $G$. These complexes appears in various places and found applications in many areas of mathematics including; discrete geometry, representation theory, combinatorics, etc. In this article, we consider the matching complexes of categorical product $P_n \\times P_m$ of path graphs $P_n$ and $P_m$. For $m = 1$, $P_n \\times P_m$ is a discrete graph and therefore its matching complex is the void complex. For $m = 2$, $\\mathsf{M}(P_n \\times P_m)$ has been proved to be homotopy equivalent to a wedge of spheres by Kozlov. We show that for $n \\geq 2$ and $3 \\leq m \\leq 5$, the matching complex of $P_n \\times P_m$ is homotopy equivalent to a wedge of spheres. For $m =3$, we give a closed form formula for the number and dimension of spheres appearing in the wedge. Further, for $m \\in \\{4, 5\\}$, we give minimum and maximum dimension of spheres appearing in the wedge in the homotopy type of $\\mathsf{M}(P_n \\times P_m)$.", "revisions": [ { "version": "v1", "updated": "2024-03-22T15:45:09.000Z" } ], "analyses": { "subjects": [ "55P10", "05E45", "55U10" ], "keywords": [ "matching complex", "path graphs", "categorical product", "homotopy equivalent", "simplicial complex" ], "note": { "typesetting": "TeX", "pages": 36, "language": "en", "license": "arXiv", "status": "editable" } } }