Eze, Leonard Chidiebere
Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia

Published : 1 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 1 Documents
Search

Analogues of Bermond-Bollobás conjecture for cages yield expander families Eze, Leonard Chidiebere; Jajcay, Robert
Electronic Journal of Graph Theory and Applications (EJGTA) Vol 14, No 1 (2026): Electronic Journal of Graph Theory and Applications
Publisher : GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/ejgta.2026.14.1.9

Abstract

This paper presents a possible link between Cages and Expander Graphs by introducing three interconnected variants of the Bermond and Bollobás Conjecture, originally formulated in 1981 within the context of the Degree/Diameter Problem. We adapt these conjectures to cages, with the most robust variant posed as follows: Does there exist a constant c such that for every pair of parameters k,g there exists a k-regular graph of girth g and order not exceeding M(k,g) + c?; where M(k,g) denotes the value of the so-called Moore bound for cages. We show that a positive answer to any of the three variants of the Bermond and Bollobás Conjecture for cages considered in our paper would yield for all k ≥ 3 the existence of k-regular expander graphs with Cheeger constant asymptotically bounded below by 1/(k-1) (expander families); thereby establishing a connection between Cages and Expander Graphs.