Explicit Rayleigh's Principles for Resistive Electrical Network and The Total Number of Spanning Trees of Graphs

TL;DR

This paper develops explicit identities for voltage and resistance functions on metrized graphs, leading to new versions of Rayleigh's Principles and formulas for the total number of spanning trees, useful for analyzing electrical networks and graph invariants.

Contribution

It introduces explicit identities for resistance and voltage functions under graph operations, extending Rayleigh's Principles and providing new formulas for spanning trees.

Findings

Derived identities for voltage and resistance functions under graph modifications

Established explicit versions of Rayleigh's Principles for electrical networks

Obtained formulas for how the total number of spanning trees changes with graph operations

Abstract

We give identities for the voltage and resistance functions on a metrized graph to show how these functions behave under any edge deletion/contraction and the identification of any two vertices. This leads to explicit versions of Rayleigh's Principles on a resistive electrical network. We also establish Euler's Identities for the resistance and the voltage functions on an electrical network. One can use these results to study various invariants of metrized graphs and electrical networks. As a specific application, we obtain various identities for the total number of spanning trees of a graph. For example, we show how the total number of spanning trees changes under graph operations such as, contraction of an edge, deletion of an edge, deletion of a vertex, the join of arbitrary two or three vertices.