{ "id": "2004.06788", "version": "v1", "published": "2020-04-14T20:07:46.000Z", "updated": "2020-04-14T20:07:46.000Z", "title": "Reflexive coloring complexes for 3-edge-colorings of cubic graphs", "authors": [ "Fiachra Knox", "Bojan Mohar", "Nathan Singer" ], "categories": [ "math.CO" ], "abstract": "Given a 3-colorable graph $X$, the 3-coloring complex $B(X)$ is the graph whose vertices are all the independent sets which occur as color classes in some 3-coloring of $X$. Two color classes $C,D \\in V(B(X))$ are joined by an edge if $C$ and $D$ appear together in a 3-coloring of $X$. The graph $B(X)$ is 3-colorable. Graphs for which $B(B(X))$ is isomorphic to $X$ are termed reflexive graphs. In this paper, we consider 3-edge-colorings of cubic graphs for which we allow half-edges. Then we consider the 3-coloring complexes of their line graphs. The main result of the paper is a surprising outcome that the line graph of any connected cubic triangle-free outerplanar graph is reflexive. We also exhibit some other interesting classes of reflexive line graphs.", "revisions": [ { "version": "v1", "updated": "2020-04-14T20:07:46.000Z" } ], "analyses": { "subjects": [ "05C15" ], "keywords": [ "cubic graphs", "reflexive coloring complexes", "color classes", "connected cubic triangle-free outerplanar graph", "independent sets" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }