## 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 self‐dual with respect to sign change. We find that the solutions to all of these counting problem
Enumeration of weak isomorphism classes of signed graphs
✍ Scribed by Tadeusz Sozański
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 869 KB
- Volume
- 4
- Category
- Article
- ISSN
- 0364-9024
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✦ Synopsis
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 lines. Some enumeration problems implied by such a definition, including the problem of self‐dual configurations, are solved here for complete signed graphs by methods of linear algebra over the two‐element field. It is also shown that weak isomorphism classes of complete signed graphs are equal in number to other configurations: unlabeled even graphs, two‐graphs and switching classes.
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