This paper deals with methods for listing all possible trees and multitrees, and for determining the relative signs of tree determinants and multitree determinants, which are necessary for the analysis of networks. A connected linear graph having

elements and all of its possible subgraphs has been studied by mapping on an

-dimensional vector space having

base vectors, and a method for finding out a number of new trees from one tree, or a set of trees, has been derived. Also, a method of computation for determining the relative signs of tree determinants has been developed. These computations can be performed easily and effectively by a digital computer provided with bitwise logical instructions.