Multiplicity lists by diameter: All trees of diameter <7
This paper considers the problem of determining all multiplicity lists occurring among Hermitian matrices whose graph is a given tree from a new perspective. For all trees of diameter <7, it is shown how to generate all possible lists. For diameter 5 and 6, this includes many nonlinear trees. In the process, for diameter 4 (double stars), the first succinct and direct description of all ordered lists, for each instance, is given. Observations of topological relationships are helpful.
Authors
- Carlos M. Saiago (ORCID: https://orcid.org/0000-0001-9843-3821)
- Charles R. Johnson (ORCID: https://orcid.org/0000-0001-8707-8596)
- Benjamin Mudrak
Institutions
- Kent State University (US)
- Virginia Research Institute (US)
- Universidade Nova de Lisboa (PT)
Publication Details
- Journal
- Linear Algebra and its Applications
- Published
- 2025-06-03
- DOI
- https://doi.org/10.1016/j.laa.2025.05.023
- Primary Topic
- Advanced Graph Theory Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Science Foundation
- Fundação para a Ciência e a Tecnologia