PreprintCC BY 4.0arXiv
Stronger Spectral Bound for Clique Number
Abstract
Given an integer k, deciding whether a graph has a clique of size k is an NP-complete problem. Wilf's inequality provides a spectral lower bound for the clique number of a graph. Strengthening this bound, Elphick and Wocjan proposed a conjecture in 2018 using positive adjacency eigenvalues. In this paper, we present an infinite family of graphs for which the Elphick and Wocjan conjecture is true. We find a stronger spectral lower bound for the clique number for this family of graphs.
Related
BibTeX
@misc{jadav2026stronger,
title = {{Stronger Spectral Bound for Clique Number}},
author = {Hareshkumar Jadav and Sudipta Mallik and Akhilesh Panchangam and Ranveer Singh},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.21388},
eprint = {2610.21388},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.21388},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Stronger Spectral Bound for Clique Number
AU - Hareshkumar Jadav
AU - Sudipta Mallik
AU - Akhilesh Panchangam
AU - Ranveer Singh
PY - 2026
DA - 2026/10/15
PB - arXiv
DO - 10.48550/arxiv.2610.21388
UR - https://arxiv.org/abs/2610.21388
AB - Given an integer k, deciding whether a graph has a clique of size k is an NP-complete problem. Wilf's inequality provides a spectral lower bound for the clique number of a graph. Strengthening this bound, Elphick and Wocjan proposed a conjecture in 2018 using positive adjacency eigenvalues. In this paper, we present an infinite family of graphs for which the Elphick and Wocjan conjecture is true. We find a stronger spectral lower bound for the clique number for this family of graphs.
ER -