Characterization of completely regular codes through p-polynomial association schemes

Author(s):  
Josep Rifà ◽  
Llorenç Huguet
2020 ◽  
Vol 36 (36) ◽  
pp. 446-460
Author(s):  
Cristina Dalfó ◽  
Miquel Àngel Fiol

It is well known that, in general, part of the spectrum of a graph can be obtained from the adjacency matrix of its quotient graph given by a regular partition. In this paper, a method that gives all the spectrum, and also the local spectra, of a graph from the quotient matrices of some of its regular partitions, is proposed. Moreover, from such partitions, the $C$-local multiplicities of any class of vertices $C$ is also determined, and some applications of these parameters in the characterization of completely regular codes and their inner distributions are described. As examples, it is shown how to find the eigenvalues and (local) multiplicities of walk-regular, distance-regular, and distance-biregular graphs.  


2019 ◽  
Vol 55 (3) ◽  
pp. 298-298
Author(s):  
J. Borges ◽  
J. Rifà ◽  
V. A. Zinoviev

2015 ◽  
Vol 9 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Joaquim Borges ◽  
◽  
Josep Rifà ◽  
Victor A. Zinoviev ◽  
◽  
...  

10.37236/172 ◽  
2009 ◽  
Vol 16 (1) ◽  
Author(s):  
M. Cámara ◽  
J. Fàbrega ◽  
M. A. Fiol ◽  
E. Garriga

We present some related families of orthogonal polynomials of a discrete variable and survey some of their applications in the study of (distance-regular) graphs and (completely regular) codes. One of the main peculiarities of such orthogonal systems is their non-standard normalization condition, requiring that the square norm of each polynomial must equal its value at a given point of the mesh. For instance, when they are defined from the spectrum of a graph, one of these families is the system of the predistance polynomials which, in the case of distance-regular graphs, turns out to be the sequence of distance polynomials. The applications range from (quasi-spectral) characterizations of distance-regular graphs, walk-regular graphs, local distance-regularity and completely regular codes, to some results on representation theory.


1991 ◽  
Vol 89 (1) ◽  
pp. 7-15 ◽  
Author(s):  
B. Courteau ◽  
A. Montpetit

Sign in / Sign up

Export Citation Format

Share Document