$k$-path graphs: experiments and conjectures about algebraic connectivity and $α$-index

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: de Paula, Rafael L., Justel, Claudia M., Oliveira, Carla S., Carauba, Milena S.
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866910098528403456
author de Paula, Rafael L.
Justel, Claudia M.
Oliveira, Carla S.
Carauba, Milena S.
author_facet de Paula, Rafael L.
Justel, Claudia M.
Oliveira, Carla S.
Carauba, Milena S.
contents This work presents conjectures about eigenvalues of matrices associated with $k$-path graphs, the algebraic connectivity, defined as the second smallest eigenvalue of the Laplacian matrix, and the $α$-index, as the largest eigenvalue of the $A_α$-matrix. For this purpose, a process based in Pereira et al., is presented to generate lists of $k$-path graphs containing all non-isomorphic 2-paths, 3-paths, and 4-paths of order $n$, for $6 \leq n \leq 26, 8 \leq n \leq 19$, and $10 \leq n \leq 18$, respectively. Using these lists, exhaustive searches for extremal graphs of fixed order for the mentioned eigenvalues were performed. Based on the empirical results, conjectures are suggested about the structure of extremal $k$-path graphs for these eigenvalues.
format Preprint
id arxiv_https___arxiv_org_abs_2511_21524
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle $k$-path graphs: experiments and conjectures about algebraic connectivity and $α$-index
de Paula, Rafael L.
Justel, Claudia M.
Oliveira, Carla S.
Carauba, Milena S.
Discrete Mathematics
Combinatorics
05C50 05C75
This work presents conjectures about eigenvalues of matrices associated with $k$-path graphs, the algebraic connectivity, defined as the second smallest eigenvalue of the Laplacian matrix, and the $α$-index, as the largest eigenvalue of the $A_α$-matrix. For this purpose, a process based in Pereira et al., is presented to generate lists of $k$-path graphs containing all non-isomorphic 2-paths, 3-paths, and 4-paths of order $n$, for $6 \leq n \leq 26, 8 \leq n \leq 19$, and $10 \leq n \leq 18$, respectively. Using these lists, exhaustive searches for extremal graphs of fixed order for the mentioned eigenvalues were performed. Based on the empirical results, conjectures are suggested about the structure of extremal $k$-path graphs for these eigenvalues.
title $k$-path graphs: experiments and conjectures about algebraic connectivity and $α$-index
topic Discrete Mathematics
Combinatorics
05C50 05C75
url https://arxiv.org/abs/2511.21524