## Abstract A signed graph is a graph in which each line has a plus or minus sign. Two signed graphs are said to be weakly isomorphic if their underlying graphs are isomorphic through a mapping under which signs of cycles are preserved, the sign of a cycle being the product of the signs of its line
Enumeration of graphs with signed points and lines
β Scribed by Frank Harary; Edgar M. Palmer; Robert W. Robinson; Allen J. Schwenk
- Publisher
- John Wiley and Sons
- Year
- 1977
- Tongue
- English
- Weight
- 485 KB
- Volume
- 1
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
Our object is to enumerate graphs in which the points or lines or both are assigned positive or negative signs. We also treat several associated problems for which these configurations are selfβdual with respect to sign change. We find that the solutions to all of these counting problems can be expressed as special cases of one general formula involving the concatenation of the cycle index of the symmetric group with that of its pair group. This counting technique is based on PΓ³lya's Enumeration Theorem and the Power Group Enumeration Theorem. Using a suitable computer program, we list the number of graphs of each type considered up to twelve points. Sharp asymptotic estimates are also obtained.
π SIMILAR VOLUMES
sequence to be the signed degree sequence of a signed graph or a signed tree, answering a question raised by
## Abstract The possible classes of balanced circles of a signed graph are characterized in two ways.
## Abstract A __full graph__ on __n__ vertices, as defined by Fulkerson, is a representation of the intersection and containment relations among a system of __n__ sets. It has an undirected edge between vertices representing intersecting sets, and a directed edge from __a__ to __b__ if the correspo