Distance-Biregular Graphs and Orthogonal Polynomials
Abstract
This thesis is about distance-biregular graphs– when they exist, what algebraic and structural properties they have, and how they arise in extremal problems.
We develop a set of necessary conditions for a distance-biregular graph to exist. Using these conditions and a computer, we develop tables of possible parameter sets for distancebiregular graphs. We extend results of Fiol, Garriga, and Yebra characterizing distance-regular graphs to characterizations of distance-biregular graphs, and highlight some new
results using these characterizations. We also extend the spectral Moore bounds of Cioaba et al. to semiregular bipartite graphs, and show that distance-biregular graphs arise as extremal examples of graphs meeting the spectral Moore bound.
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Cite this version of the work
Sabrina Lato
(2023).
Distance-Biregular Graphs and Orthogonal Polynomials. UWSpace.
http://hdl.handle.net/10012/19866
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