Abstract
For a nontrivial connected graph G of order n and a linear ordering s: v 1, v 2, …, v n of vertices of G, define \( d(s) = \sum\limits_{i = 1}^{n - 1} {d(v_i ,v_{i + 1} )} \). The traceable number t(G) of a graph G is t(G) = min{d(s)} and the upper traceable number t +(G) of G is t +(G) = max{d(s)}, where the minimum and maximum are taken over all linear orderings s of vertices of G. We study upper traceable numbers of several classes of graphs and the relationship between the traceable number and upper traceable number of a graph. All connected graphs G for which t +(G) − t(G) = 1 are characterized and a formula for the upper traceable number of a tree is established.
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Research supported by Srinakharinwirot University, the Thailand Research Fund and the Commission on Higher Education, Thailand under the grant number MRG 5080075.
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Okamoto, F., Zhang, P. & Saenpholphat, V. The upper traceable number of a graph. Czech Math J 58, 271–287 (2008). https://doi.org/10.1007/s10587-008-0016-9
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DOI: https://doi.org/10.1007/s10587-008-0016-9