Title
Counting arithmetical structures on paths and cycles.
Abstract
Let G be a finite, connected graph. An arithmetical structure on G is a pair of positive integer vectors d,r such that (diag(d)−A)r=0, where A is the adjacency matrix of G. We investigate the combinatorics of arithmetical structures on path and cycle graphs, as well as the associated critical groups (the torsion part of the cokernels of the matrices (diag(d)−A)). For paths, we prove that arithmetical structures are enumerated by the Catalan numbers, and we obtain refined enumeration results related to ballot sequences. For cycles, we prove that arithmetical structures are enumerated by the binomial coefficients 2n−1n−1, and we obtain refined enumeration results related to multisets. In addition, we determine the critical groups for all arithmetical structures on paths and cycles.
Year
DOI
Venue
2018
10.1016/j.disc.2018.07.002
Discrete Mathematics
Keywords
Field
DocType
Arithmetical graph,Ballot number,Catalan number,Critical group,Sandpile group,Laplacian
Integer,Adjacency matrix,Discrete mathematics,Arithmetic function,Combinatorics,Matrix (mathematics),Catalan number,Enumeration,Binomial coefficient,Connectivity,Mathematics
Journal
Volume
Issue
ISSN
341
10
0012-365X
Citations 
PageRank 
References 
0
0.34
2
Authors
9