{ "id": "2306.15818", "version": "v1", "published": "2023-06-27T22:23:24.000Z", "updated": "2023-06-27T22:23:24.000Z", "title": "Total mutual-visibility in graphs with emphasis on lexicographic and Cartesian products", "authors": [ "Dorota Kuziak", "Juan A. Rodríguez-Velázquez" ], "categories": [ "math.CO" ], "abstract": "Given a connected graph $G$, the total mutual-visibility number of $G$, denoted $\\mu_t(G)$, is the cardinality of a largest set $S\\subseteq V(G)$ such that for every pair of vertices $x,y\\in V(G)$ there is a shortest $x,y$-path whose interior vertices are not contained in $S$. Several combinatorial properties, including bounds and closed formulae, for $\\mu_t(G)$ are given in this article. Specifically, we give several bounds for $\\mu_t(G)$ in terms of the diameter, order and/or connected domination number of $G$ and show characterizations of the graphs achieving the limit values of some of these bounds. We also consider those vertices of a graph $G$ that either belong to every total mutual-visibility set of $G$ or does not belong to any of such sets, and deduce some consequences of these results. We determine the exact value of the total mutual-visibility number of lexicographic products in terms of the orders of the factors, and the total mutual-visibility number of the first factor in the product. Finally, we give some bounds and closed formulae for the total mutual-visibility number of Cartesian product graphs.", "revisions": [ { "version": "v1", "updated": "2023-06-27T22:23:24.000Z" } ], "analyses": { "keywords": [ "total mutual-visibility number", "cartesian product graphs", "closed formulae", "total mutual-visibility set", "lexicographic products" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }