A matrix representation of graphs and its spectrum as a graph invariant

dc.creatorEmms, David
dc.creatorHancock, Edwin R.
dc.creatorSeverini, Simone
dc.creatorWilson, Richard C.
dc.date2005-05-05
dc.date2006-04-05
dc.date.accessioned2026-07-07T06:40:58Z
dc.date.available2026-07-07T06:40:58Z
dc.descriptionWe use the line digraph construction to associate an orthogonal matrix with each graph. From this orthogonal matrix, we derive two further matrices. The spectrum of each of these three matrices is considered as a graph invariant. For the first two cases, we compute the spectrum explicitly and show that it is determined by the spectrum of the adjacency matrix of the original graph. We then show by computation that the isomorphism classes of many known families of strongly regular graphs (up to 64 vertices) are characterized by the spectrum of this matrix. We conjecture that this is always the case for strongly regular graphs and we show that the conjecture is not valid for general graphs. We verify that the smallest regular graphs which are not distinguished with our method are on 14 vertices.
dc.description14 pages
dc.identifierhttps://arxiv.org/abs/quant-ph/0505026
dc.identifierhttp://arxiv.org/abs/quant-ph/0505026
dc.identifierThe Electronic Journal of Combinatorics 13 (2006), #R34
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/101547
dc.subjectQuantum Physics
dc.titleA matrix representation of graphs and its spectrum as a graph invariant
dc.typetext

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