An Efficient Algorithm for Path Matrix Computation and Improved Path Energy Bounds
摘要
The path matrix and path energy of a graph provide valuable insights into structural properties related to vertex-disjoint paths. In this paper, we present a new algorithm for computing the all-pairs path matrix of undirected graphs. The method employs Gomory-Hu trees with fast unit-capacity max-flow computations, achieving a time complexity of \(O(|V|\,|E|\sqrt{|E|} + |V|^2)\) . We further establish new bounds for the path energy in terms of the maximum degree and the Frobenius norm, which improve upon the existing bound of \(2(n-1)^2\) and give sharper estimates for all non-complete graphs. In addition, we demonstrate a connection between classical graph energy and path energy, thereby contributing to the broader framework of spectral graph theory.