567 research outputs found

    Maker-Breaker domination number

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    The Maker-Breaker domination game is played on a graph GG by Dominator and Staller. The players alternatively select a vertex of GG that was not yet chosen in the course of the game. Dominator wins if at some point the vertices he has chosen form a dominating set. Staller wins if Dominator cannot form a dominating set. In this paper we introduce the Maker-Breaker domination number γMB(G)\gamma_{{\rm MB}}(G) of GG as the minimum number of moves of Dominator to win the game provided that he has a winning strategy and is the first to play. If Staller plays first, then the corresponding invariant is denoted γMB(G)\gamma_{{\rm MB}}'(G). Comparing the two invariants it turns out that they behave much differently than the related game domination numbers. The invariant γMB(G)\gamma_{{\rm MB}}(G) is also compared with the domination number. Using the Erd\H{o}s-Selfridge Criterion a large class of graphs GG is found for which γMB(G)>γ(G)\gamma_{{\rm MB}}(G) > \gamma(G) holds. Residual graphs are introduced and used to bound/determine γMB(G)\gamma_{{\rm MB}}(G) and γMB(G)\gamma_{{\rm MB}}'(G). Using residual graphs, γMB(T)\gamma_{{\rm MB}}(T) and γMB(T)\gamma_{{\rm MB}}'(T) are determined for an arbitrary tree. The invariants are also obtained for cycles and bounded for union of graphs. A list of open problems and directions for further investigations is given.Comment: 20 pages, 5 figure

    All Maximal Independent Sets and Dynamic Dominance for Sparse Graphs

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    We describe algorithms, based on Avis and Fukuda's reverse search paradigm, for listing all maximal independent sets in a sparse graph in polynomial time and delay per output. For bounded degree graphs, our algorithms take constant time per set generated; for minor-closed graph families, the time is O(n) per set, and for more general sparse graph families we achieve subquadratic time per set. We also describe new data structures for maintaining a dynamic vertex set S in a sparse or minor-closed graph family, and querying the number of vertices not dominated by S; for minor-closed graph families the time per update is constant, while it is sublinear for any sparse graph family. We can also maintain a dynamic vertex set in an arbitrary m-edge graph and test the independence of the maintained set in time O(sqrt m) per update. We use the domination data structures as part of our enumeration algorithms.Comment: 10 page

    Resolving sets for breaking symmetries of graphs

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    This paper deals with the maximum value of the difference between the determining number and the metric dimension of a graph as a function of its order. Our technique requires to use locating-dominating sets, and perform an independent study on other functions related to these sets. Thus, we obtain lower and upper bounds on all these functions by means of very diverse tools. Among them are some adequate constructions of graphs, a variant of a classical result in graph domination and a polynomial time algorithm that produces both distinguishing sets and determining sets. Further, we consider specific families of graphs where the restrictions of these functions can be computed. To this end, we utilize two well-known objects in graph theory: kk-dominating sets and matchings.Comment: 24 pages, 12 figure
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