{ "id": "1606.03751", "version": "v1", "published": "2016-06-12T18:37:23.000Z", "updated": "2016-06-12T18:37:23.000Z", "title": "Distinguishing number and distinguishing index of neighbourhood corona of two graphs", "authors": [ "Saeid Alikhani", "Samaneh Soltani" ], "comment": "15 pages, 11 figures", "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 labeling (edge labeling) with $d$ labels that is preserved only by a trivial automorphism. The neighbourhood corona of two graphs $G_1$ and $G_2$ is denoted by $G_1 \\star G_2$ and is the graph obtained by taking one copy of $G_1$ and $|V(G_1)|$ copies of $G_2$, and joining the neighbours of the $i$th vertex of $G_1$ to every vertex in the $i$th copy of $G_2$. In this paper we describe the automorphisms of the graph $G_1\\star G_2$. Using results on automorphisms, we study the distinguishing number and the distinguishing index of $G_1\\star G_2$. We obtain upper bounds for $D(G_1\\star G_2)$ and $D'(G_1\\star G_2)$.", "revisions": [ { "version": "v1", "updated": "2016-06-12T18:37:23.000Z" } ], "analyses": { "subjects": [ "05C15", "05E18" ], "keywords": [ "distinguishing number", "neighbourhood corona", "distinguishing index", "trivial automorphism", "th vertex" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable" } } }