87 research outputs found

    A Characterisation of Weak Integer Additive Set-Indexers of Graphs

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    An integer additive set-indexer is defined as an injective function f:V(G)β†’2N0f:V(G)\rightarrow 2^{\mathbb{N}_0} such that the induced function gf:E(G)β†’2N0g_f:E(G) \rightarrow 2^{\mathbb{N}_0} defined by gf(uv)=f(u)+f(v)g_f (uv) = f(u)+ f(v) is also injective. An integer additive set-indexer is said to be kk-uniform if ∣gf(e)∣=k|g_f(e)| = k for all e∈E(G)e\in E(G). An integer additive set-indexer ff is said to be a weak integer additive set-indexer if ∣gf(uv)∣=max(∣f(u)∣,∣f(v)∣)|g_f(uv)|=max(|f(u)|,|f(v)|) for all u,v∈V(G)u,v\in V(G). In this paper, we study the characteristics of certain graphs and graph classes which admit weak integer additive set-indexers.Comment: 12pages, 4 figures, arXiv admin note: text overlap with arXiv:1311.085

    Strong Integer Additive Set-valued Graphs: A Creative Review

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    For a non-empty ground set XX, finite or infinite, the {\em set-valuation} or {\em set-labeling} of a given graph GG is an injective function f:V(G)β†’P(X)f:V(G) \to \mathcal{P}(X), where P(X)\mathcal{P}(X) is the power set of the set XX. A set-indexer of a graph GG is an injective set-valued function f:V(G)β†’P(X)f:V(G) \to \mathcal{P}(X) such that the function fβˆ—:E(G)β†’P(X)βˆ’{βˆ…}f^{\ast}:E(G)\to \mathcal{P}(X)-\{\emptyset\} defined by fβˆ—(uv)=f(u)βˆ—f(v)f^{\ast}(uv) = f(u){\ast} f(v) for every uv∈E(G)uv{\in} E(G) is also injective., where βˆ—\ast is a binary operation on sets. An integer additive set-indexer is defined as an injective function f:V(G)β†’P(N0)f:V(G)\to \mathcal{P}({\mathbb{N}_0}) such that the induced function gf:E(G)β†’P(N0)g_f:E(G) \to \mathcal{P}(\mathbb{N}_0) defined by gf(uv)=f(u)+f(v)g_f (uv) = f(u)+ f(v) is also injective, where N0\mathbb{N}_0 is the set of all non-negative integers and P(N0)\mathcal{P}(\mathbb{N}_0) is its power set. An IASI ff is said to be a strong IASI if ∣f+(uv)∣=∣f(u)βˆ£β€‰βˆ£f(v)∣|f^+(uv)|=|f(u)|\,|f(v)| for every pair of adjacent vertices u,vu,v in GG. In this paper, we critically and creatively review the concepts and properties of strong integer additive set-valued graphs.Comment: 13 pages, Published. arXiv admin note: text overlap with arXiv:1407.4677, arXiv:1405.4788, arXiv:1310.626

    On Integer Additive Set-Indexers of Graphs

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    A set-indexer of a graph GG is an injective set-valued function f:V(G)β†’2Xf:V(G) \rightarrow2^{X} such that the function fβŠ•:E(G)β†’2Xβˆ’{βˆ…}f^{\oplus}:E(G)\rightarrow2^{X}-\{\emptyset\} defined by fβŠ•(uv)=f(u)βŠ•f(v)f^{\oplus}(uv) = f(u){\oplus} f(v) for every uv∈E(G)uv{\in} E(G) is also injective, where 2X2^{X} is the set of all subsets of XX and βŠ•\oplus is the symmetric difference of sets. An integer additive set-indexer is defined as an injective function f:V(G)β†’2N0f:V(G)\rightarrow 2^{\mathbb{N}_0} such that the induced function gf:E(G)β†’2N0g_f:E(G) \rightarrow 2^{\mathbb{N}_0} defined by gf(uv)=f(u)+f(v)g_f (uv) = f(u)+ f(v) is also injective. A graph GG which admits an IASI is called an IASI graph. An IASI ff is said to be a {\em weak IASI} if ∣gf(uv)∣=max(∣f(u)∣,∣f(v)∣)|g_f(uv)|=max(|f(u)|,|f(v)|) and an IASI ff is said to be a {\em strong IASI} if ∣gf(uv)∣=∣f(u)∣∣f(v)∣|g_f(uv)|=|f(u)| |f(v)| for all u,v∈V(G)u,v\in V(G). In this paper, we study about certain characteristics of inter additive set-indexers.Comment: 12 pages. arXiv admin note: text overlap with arXiv:1312.7674 To Appear in Int. J. Math. Sci.& Engg. Appl. in March 201

    A Creative Review on Integer Additive Set-Valued Graphs

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    For a non-empty ground set XX, finite or infinite, the {\em set-valuation} or {\em set-labeling} of a given graph GG is an injective function f:V(G)β†’P(X)f:V(G) \to \mathcal{P}(X), where P(X)\mathcal{P}(X) is the power set of the set XX. A set-indexer of a graph GG is an injective set-valued function f:V(G)β†’P(X)f:V(G) \to \mathcal{P}(X) such that the function fβˆ—:E(G)β†’P(X)βˆ’{βˆ…}f^{\ast}:E(G)\to \mathcal{P}(X)-\{\emptyset\} defined by fβˆ—(uv)=f(u)βˆ—f(v)f^{\ast}(uv) = f(u){\ast} f(v) for every uv∈E(G)uv{\in} E(G) is also injective, where βˆ—\ast is a binary operation on sets. An integer additive set-indexer is defined as an injective function f:V(G)β†’P(N0)f:V(G)\to \mathcal{P}({\mathbb{N}_0}) such that the induced function f+:E(G)β†’P(N0)f^+:E(G) \to \mathcal{P}(\mathbb{N}_0) defined by f+(uv)=f(u)+f(v)f^+ (uv) = f(u)+ f(v) is also injective, where N0\mathbb{N}_0 is the set of all non-negative integers. In this paper, we critically and creatively review the concepts and properties of integer additive set-valued graphs.Comment: 14 pages, submitted. arXiv admin note: text overlap with arXiv:1312.7672, arXiv:1312.767

    Further Studies on the Sparing Number of Graphs

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    Let N0\mathbb{N}_0 denote the set of all non-negative integers and P(N0)\mathcal{P}(\mathbb{N}_0) be its power set. An integer additive set-indexer is an injective function f:V(G)β†’P(N0)f:V(G)\to \mathcal{P}(\mathbb{N}_0) such that the induced function f+:E(G)β†’P(N0)f^+:E(G) \to \mathcal{P}(\mathbb{N}_0) defined by f+(uv)=f(u)+f(v)f^+ (uv) = f(u)+ f(v) is also injective, where f(u)+f(v)f(u)+f(v) is the sum set of f(u)f(u) and f(v)f(v). If f+(uv)=kΒ βˆ€Β uv∈E(G)f^+(uv)=k~\forall~uv\in E(G), then ff is said to be a kk-uniform integer additive set-indexer. An integer additive set-indexer ff is said to be a weak integer additive set-indexer if ∣f+(uv)∣=max⁑(∣f(u)∣,∣f(v)∣)Β βˆ€Β uv∈E(G)|f^+(uv)|=\max(|f(u)|,|f(v)|)~\forall ~ uv\in E(G). In this paper, we study the admissibility of weak integer additive set-indexer by certain graphs and graph operations.Comment: 10 Pages, Submitted. arXiv admin note: substantial text overlap with arXiv:1310.609

    Associated Graphs of Certain Arithmetic IASI Graphs

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    An integer additive set-indexer is defined as an injective function f:V(G)β†’2N0f:V(G)\rightarrow 2^{\mathbb{N}_0} such that the induced function f+:E(G)β†’2N0f^+:E(G) \rightarrow 2^{\mathbb{N}_0} defined by f+(uv)=f(u)+f(v)f^+ (uv) = f(u)+ f(v) is also injective. A graph GG which admits an IASI is called an IASI graph. An arithmetic integer additive set-indexer is an integer additive set-indexer ff, under which the set-labels of all elements of a given graph GG are arithmetic progressions. In this paper, we discuss about admissibility of arithmetic integer additive set-indexers by certain associated graphs of the given graph GG, like line graph, total graph, etc.Comment: 11 pages. arXiv admin note: text overlap with arXiv:1312.7674, arXiv:1312.767
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