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Distance-regular graphs with a few q-distance eigenvalues [PDF]

open access: yesDiscrete Mathematics
In this paper we study when the $q$-distance matrix of a distance-regular graph has few distinct eigenvalues. We mainly concentrate on diameter 3.
Mamoon Abdullah   +3 more
exaly   +2 more sources

Addressing graph products and distance-regular graphs [PDF]

open access: yesDiscrete Applied Mathematics, 2016
Graham and Pollak showed that the vertices of any connected graph $G$ can be assigned $t$-tuples with entries in $\{0, a, b\}$, called addresses, such that the distance in $G$ between any two vertices equals the number of positions in their addresses ...
S. Cioabă   +4 more
semanticscholar   +5 more sources

Distance-regular graphs [PDF]

open access: yesThe Electronic Journal of Combinatorics, 2014
This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the ...
E. V. van Dam, J. Koolen, Hajime Tanaka
semanticscholar   +5 more sources

On almost distance-regular graphs [PDF]

open access: yesJournal of Combinatorial Theory - Series A, 2011
Distance-regular graphs are a key concept in Algebraic Combinatorics and have given rise to several generalizations, such as association schemes. Motivated by spectral and other algebraic characterizations of distance-regular graphs, we study `almost distance-regular graphs'.
Cristina Dalfó, E Garriga, M A Fiol
exaly   +11 more sources

On the coset graph construction of distance-regular graphs

open access: yesDiscrete Mathematics, 2022
We show that no more new distance-regular graphs in the tables of the book of (Brouwer, Cohen, Neumaier, 1989) can be produced by using the coset graph of additive completely regular codes over finite fields.
Patrick Sole   +2 more
exaly   +5 more sources

Nonexistence of a Class of Distance-Regular Graphs

open access: yesThe Electronic Journal of Combinatorics, 2015
Let $\Gamma$ denote a distance-regular graph with diameter $D \geq 3$ and intersection numbers $a_1=0, a_2 \neq 0$, and $c_2=1$. We show a connection between the $d$-bounded property and the nonexistence of parallelograms of any length up to $d+1 ...
Yu-pei Huang   +2 more
semanticscholar   +4 more sources

m-Distance-regular graphs and their relation to multivariate P-polynomial association schemes [PDF]

open access: yesDiscrete Mathematics, 2023
An association scheme is $P$-polynomial if and only if it consists of the distance matrices of a distance-regular graph. Recently, bivariate $P$-polynomial association schemes of type $(\alpha,\beta)$ were introduced by Bernard et al., and multivariate ...
Pierre-Antoine Bernard   +4 more
semanticscholar   +1 more source

A valency bound for distance-regular graphs

open access: yesJournal of Combinatorial Theory - Series A, 2018
Zhi Qiao, Jack Koolen
exaly   +2 more sources

POSITIVITY OF GIBBS STATES ON DISTANCE-REGULAR GRAPHS [PDF]

open access: yesInfinite Dimensional Analysis Quantum Probability and Related Topics, 2021
We study criteria which ensure that Gibbs states (often also called generalized vacuum states) on distance-regular graphs are positive. Our main criterion assumes that the graph can be embedded into a growing family of distance-regular graphs.
M. Voit
semanticscholar   +1 more source

On distance labelings of 2-regular graphs

open access: yesElectronic Journal of Graph Theory and Applications, 2021
Let G  be a graph with |V(G)| vertices and ψ :  V(G) → {1, 2, 3, ... , |V(G)|} be a bijective function. The weight of a vertex v ∈ V(G) under ψ is wψ(v) = ∑u ∈ N(v)ψ(u).  The function ψ is called a distance magic labeling of G, if wψ(v) is a constant for
Anak Agung Gede Ngurah   +1 more
doaj   +1 more source

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