10,596 research outputs found

    Trees with paired-domination number twice their domination number

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    Using Domination to Analyze RNA Structures.

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    Understanding RNA molecules is important to genomics research. Recently researchers at the Courant Institute of Mathematical Sciences used graph theory to model RNA molecules and provided a database of trees representing possible secondary RNA structures. In this thesis we use domination parameters to predict which trees are more likely to exist in nature as RNA structures. This approach appears to have promise in graph theory applications in genomics research

    Disjoint Dominating Sets with a Perfect Matching

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    In this paper, we consider dominating sets DD and D′D' such that DD and D′D' are disjoint and there exists a perfect matching between them. Let DDm(G)DD_{\textrm{m}}(G) denote the cardinality of smallest such sets D,D′D, D' in GG (provided they exist, otherwise DDm(G)=∞DD_{\textrm{m}}(G) = \infty). This concept was introduced in [Klostermeyer et al., Theory and Application of Graphs, 2017] in the context of studying a certain graph protection problem. We characterize the trees TT for which DDm(T)DD_{\textrm{m}}(T) equals a certain graph protection parameter and for which DDm(T)=α(T)DD_{\textrm{m}}(T) = \alpha(T), where α(G)\alpha(G) is the independence number of GG. We also further study this parameter in graph products, e.g., by giving bounds for grid graphs, and in graphs of small independence number

    A characterization of (2γ,γp)-trees

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    AbstractLet G=(V,E) be a graph. A set S⊆V is a dominating set of G if every vertex not in S is adjacent with some vertex in S. The domination number of G, denoted by γ(G), is the minimum cardinality of a dominating set of G. A set S⊆V is a paired-dominating set of G if S dominates V and 〈S〉 contains at least one perfect matching. The paired-domination number of G, denoted by γp(G), is the minimum cardinality of a paired-dominating set of G. In this paper, we provide a constructive characterization of those trees for which the paired-domination number is twice the domination number
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