{ "id": "2409.01729", "version": "v2", "published": "2024-09-03T09:13:12.000Z", "updated": "2025-06-21T06:40:52.000Z", "title": "On the fractional matching extendability of Cayley graphs of Abelian groups", "authors": [ "Boštjan Kuzman", "Primož Šparl" ], "comment": "21 pages, this is a revised version submitted to the Electronic Journal of Combinatorics", "categories": [ "math.CO" ], "abstract": "Fractional matching extendability is a concept that brings together two widely studied topics in graph theory, namely that of fractional matchings and that of matching extendability. A {\\em fractional matching} of a graph $\\Gamma$ with edge set $E$ is a function $f$ from $E$ to the real interval $[0,1]$ with the property that for each vertex $v$ of $\\Gamma$, the sum of $f$-values of all the edges incident to $v$ is at most $1$. When this sum equals $1$ for each vertex $v$, the fractional matching is {\\em perfect}. A graph of order at least $2t+1$ is {\\em fractional $t$-extendable} if it contains a matching of size $t$ and if each such matching $M$ can be extended to a fractional perfect matching in the sense that the corresponding function $f$ assigns value $1$ to each edge of $M$. In this paper, we study fractional matching extendability of Cayley graphs of Abelian groups. We show that, except for the odd cycles, all connected Cayley graphs of Abelian groups are fractional $1$-extendable and we classify the fractional $2$-extendable Cayley graphs of Abelian groups. This extends the classification of $2$-extendable (in the classical sense) connected Cayley graphs of Abelian groups of even order from 1995, obtained by Chan, Chen and Yu.", "revisions": [ { "version": "v2", "updated": "2025-06-21T06:40:52.000Z" } ], "analyses": { "subjects": [ "05C70", "05C25" ], "keywords": [ "abelian groups", "connected cayley graphs", "study fractional matching extendability", "graph theory", "edges incident" ], "note": { "typesetting": "TeX", "pages": 21, "language": "en", "license": "arXiv", "status": "editable" } } }