Tutte polynomial of pseudofractal scale-free web

TL;DR

This paper derives recursive formulas for the Tutte polynomial of pseudofractal scale-free web, enabling efficient computation and analysis of network invariants, and compares its robustness to that of Sierpinski gasket.

Contribution

It provides recursive formulas for the Tutte polynomial of PSW and analyzes its network robustness, offering new insights into scale-free versus regular networks.

Findings

Logarithmic complexity algorithm for Tutte polynomial of PSW

Explicit calculation of the number of spanning trees in PSW

Sierpinski gasket is more robust against edge failures than PSW

Abstract

The Tutte polynomial of a graph is a 2-variable polynomial which is quite important in both combinatorics and statistical physics. It contains various numerical invariants and polynomial invariants, such as the number of spanning trees, the number of spanning forests, the number of acyclic orientations, the reliability polynomial, chromatic polynomial and flow polynomial. In this paper, we study and gain recursive formulas for the Tutte polynomial of pseudofractal scale-free web (PSW) which implies logarithmic complexity algorithm is obtained to calculate the Tutte polynomial of PSW although it is NP-hard for general graph. We also obtain the rigorous solution for the the number of spanning trees of PSW by solving the recurrence relations derived from Tutte polynomial, which give an alternative approach for explicitly determining the number of spanning trees of PSW. Further more, we analysis the all-terminal reliability of PSW and compare the results with that of Sierpinski gasket which has the same number of nodes and edges with PSW. In contrast with the well-known conclusion that scale-free networks are more robust against removal of nodes than homogeneous networks (e.g., exponential networks and regular networks). Our results show that Sierpinski gasket (which is a regular network) are more robust against random edge failures than PSW (which is a scale-free network). Whether it is true for any regular networks and scale-free networks, is still a unresolved problem.