{ "id": "1710.08143", "version": "v1", "published": "2017-10-23T08:33:34.000Z", "updated": "2017-10-23T08:33:34.000Z", "title": "The distinguishing index of graphs with at least one cycle is not more than its distinguishing number", "authors": [ "Saeid Alikhani", "Samaneh Soltani" ], "categories": [ "math.CO" ], "abstract": "The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the least integer $d$ such that $G$ has an vertex (edge) labeling with $d$ labels that is preserved only by the trivial automorphism. It is known that for every graph $G$ we have $D'(G) \\leq D(G) + 1$. The complete characterization of finite trees $T$ with $D'(T)=D(T)+ 1$ has been given recently. In this note we show that if $G$ is a finite connected graph with at least one cycle, then $D'(G)\\leq D(G)$. Finally, we characterize all connected graphs for which $D'(G) \\leq D(G)$.", "revisions": [ { "version": "v1", "updated": "2017-10-23T08:33:34.000Z" } ], "analyses": { "subjects": [ "05C15", "05E18" ], "keywords": [ "distinguishing number", "distinguishing index", "complete characterization", "trivial automorphism", "finite trees" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }