{ "id": "2111.03298", "version": "v1", "published": "2021-11-05T07:21:50.000Z", "updated": "2021-11-05T07:21:50.000Z", "title": "Relating the total domination number and the annihilation number for quasi-trees and some composite graphs", "authors": [ "Hongbo Hua", "Xinying Hua", "Sandi Klavžar", "Kexiang Xu" ], "categories": [ "math.CO" ], "abstract": "The total domination number $\\gamma_{t}(G)$ of a graph $G$ is the cardinality of a smallest set $D\\subseteq V(G)$ such that each vertex of $G$ has a neighbor in $D$. The annihilation number $a(G)$ of $G$ is the largest integer $k$ such that there exist $k$ different vertices in $G$ with the degree sum at most $m(G)$. It is conjectured that $\\gamma_{t}(G)\\leq a(G)+1$ holds for every nontrivial connected graph $G$. The conjecture has been proved for graphs with minimum degree at least $3$, trees, certain tree-like graphs, block graphs, and cactus graphs. In the main result of this paper it is proved that the conjecture holds for quasi-trees. The conjecture is verified also for some graph constructions including bijection graphs, Mycielskians, and the newly introduced universally-identifying graphs.", "revisions": [ { "version": "v1", "updated": "2021-11-05T07:21:50.000Z" } ], "analyses": { "keywords": [ "total domination number", "annihilation number", "composite graphs", "quasi-trees", "conjecture" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }