{ "id": "2312.15464", "version": "v1", "published": "2023-12-24T11:50:39.000Z", "updated": "2023-12-24T11:50:39.000Z", "title": "$k$-Domination invariants on Kneser graphs", "authors": [ "Boštjan Brešar", "María Gracia Cornet", "Tanja Dravec", "Michael A. Henning" ], "comment": "15 pages, 3 tables", "categories": [ "math.CO" ], "abstract": "In this follow-up to [M.G.~Cornet, P.~Torres, arXiv:2308.15603], where the $k$-tuple domination number and the 2-packing number in Kneser graphs $K(n,r)$ were studied, we are concerned with two variations, the $k$-domination number, ${\\gamma_{k}}(K(n,r))$, and the $k$-tuple total domination number, ${\\gamma_{t\\times k}}(K(n,r))$, of $K(n,r)$. For both invariants we prove monotonicity results by showing that ${\\gamma_{k}}(K(n,r))\\ge {\\gamma_{k}}(K(n+1,r))$ holds for any $n\\ge 2(k+r)$, and ${\\gamma_{t\\times k}}(K(n,r))\\ge {\\gamma_{t\\times k}}(K(n+1,r))$ holds for any $n\\ge 2r+1$. We prove that ${\\gamma_{k}}(K(n,r))={\\gamma_{t\\times k}}(K(n,r))=k+r$ when $n\\geq r(k+r)$, and that in this case every ${\\gamma_{k}}$-set and ${\\gamma_{t\\times k}}$-set is a clique, while ${\\gamma_{k}}(r(k+r)-1,r)={\\gamma_{t\\times k}}(r(k+r)-1,r)=k+r+1$, for any $k\\ge 2$. Concerning the 2-packing number, $\\rho_2(K(n,r))$, of $K(n,r)$, we prove the exact values of $\\rho_2(K(3r-3,r))$ when $r\\ge 10$, and give sufficient conditions for $\\rho_2(K(n,r))$ to be equal to some small values by imposing bounds on $r$ with respect to $n$. We also prove a version of monotonicity for the $2$-packing number of Kneser graphs.", "revisions": [ { "version": "v1", "updated": "2023-12-24T11:50:39.000Z" } ], "analyses": { "subjects": [ "05C69", "05D05" ], "keywords": [ "kneser graphs", "domination invariants", "tuple total domination number", "tuple domination number", "sufficient conditions" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable" } } }