628 research outputs found

    An Algorithm for Odd Graceful Labeling of the Union of Paths and Cycles

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    In 1991, Gnanajothi [4] proved that the path graph P_n with n vertex and n-1 edge is odd graceful, and the cycle graph C_m with m vertex and m edges is odd graceful if and only if m even, she proved the cycle graph is not graceful if m odd. In this paper, firstly, we studied the graph C_m ∪\cup P_m when m = 4, 6,8,10 and then we proved that the graph C_ ∪\cup P_n is odd graceful if m is even. Finally, we described an algorithm to label the vertices and the edges of the vertex set V(C_m ∪\cup P_n) and the edge set E(C_m ∪\cup P_n).Comment: 9 Pages, JGraph-Hoc Journa

    Vertex Graceful Labeling-Some Path Related Graphs

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    Treating subjects as vertex graceful graphs, vertex graceful labeling, caterpillar, actinia graphs, Smarandachely vertex m-labeling

    On the Graceful Game

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    A graceful labeling of a graph GG with mm edges consists of labeling the vertices of GG with distinct integers from 00 to mm such that, when each edge is assigned as induced label the absolute difference of the labels of its endpoints, all induced edge labels are distinct. Rosa established two well known conjectures: all trees are graceful (1966) and all triangular cacti are graceful (1988). In order to contribute to both conjectures we study graceful labelings in the context of graph games. The Graceful game was introduced by Tuza in 2017 as a two-players game on a connected graph in which the players Alice and Bob take turns labeling the vertices with distinct integers from 0 to mm. Alice's goal is to gracefully label the graph as Bob's goal is to prevent it from happening. In this work, we study winning strategies for Alice and Bob in complete graphs, paths, cycles, complete bipartite graphs, caterpillars, prisms, wheels, helms, webs, gear graphs, hypercubes and some powers of paths

    On the number of unlabeled vertices in edge-friendly labelings of graphs

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    Let GG be a graph with vertex set V(G)V(G) and edge set E(G)E(G), and ff be a 0-1 labeling of E(G)E(G) so that the absolute difference in the number of edges labeled 1 and 0 is no more than one. Call such a labeling ff \emph{edge-friendly}. We say an edge-friendly labeling induces a \emph{partial vertex labeling} if vertices which are incident to more edges labeled 1 than 0, are labeled 1, and vertices which are incident to more edges labeled 0 than 1, are labeled 0. Vertices that are incident to an equal number of edges of both labels we call \emph{unlabeled}. Call a procedure on a labeled graph a \emph{label switching algorithm} if it consists of pairwise switches of labels. Given an edge-friendly labeling of KnK_n, we show a label switching algorithm producing an edge-friendly relabeling of KnK_n such that all the vertices are labeled. We call such a labeling \textit{opinionated}.Comment: 7 pages, accepted to Discrete Mathematics, special issue dedicated to Combinatorics 201
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