Topological patterns identification for sneak circuit analysis

In sneak circuit analysis, it demands to identify the basic topological patterns which are the causes of sneak circuits. In this paper we formulate the problem of identifying the basic topological patterns into that of enumerating subgraphs homeomorphic to five specific signed trees in signed graphs, and give methods to simplify signed graphs and an algorithm to find all paths from a given vertex to a set of vertices of degree one in a graph. We propose a sketch algorithm for enumerating subgraphs homeomorphic to the specific signed trees and present an example of topological patterns identification using our methods.