<p>The transmission of a vertex <i>v</i> in a (chemical) graph <i>G</i> is the sum of distances from <i>v</i> to other vertices in <i>G</i>. If any two vertices of <i>G</i> have different transmissions, then <i>G</i> is transmission irregular. The Wiener index <i>W</i>(<i>G</i>) of a graph <i>G</i> is the sum of all distances between all unordered pairs of vertices in <i>G</i>, which has another formula as the half of the sum of transmissions of all vertices of <i>G</i>. In this paper, we consider the Wiener index maximization problem on the set of transmission irregular trees of a given order <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(n \in {\mathbb {N}}\)</EquationSource> </InlineEquation>. We solve the problem for all odd values of <i>n</i> and for almost all even values of <i>n</i>. Each resolved extremal problem has a unique solution that is a chemical tree.</p>

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On the transmission irregular trees with the maximum Wiener index

  • Ivan Damnjanović,
  • Anran Xu,
  • Kexiang Xu

摘要

The transmission of a vertex v in a (chemical) graph G is the sum of distances from v to other vertices in G. If any two vertices of G have different transmissions, then G is transmission irregular. The Wiener index W(G) of a graph G is the sum of all distances between all unordered pairs of vertices in G, which has another formula as the half of the sum of transmissions of all vertices of G. In this paper, we consider the Wiener index maximization problem on the set of transmission irregular trees of a given order \(n \in {\mathbb {N}}\) . We solve the problem for all odd values of n and for almost all even values of n. Each resolved extremal problem has a unique solution that is a chemical tree.