Scientific article
English

Not Every Uniform Tree Covers Ramanujan Graphs

Published inJournal of combinatorial theory. Series B, vol. 74, no. 2, p. 202-212
Publication date1998
Abstract

The notion of Ramanujan graph has been extended to not necessarily regular graphs by Y. Greenberg. We construct infinite trees with infinitely many finite quotients, none of which is Ramanujan. We give a sufficient condition for a finite graph to be covered by such a tree.

Keywords
  • Ramanujan graph
  • Covering tree
  • Spectral radius
  • Mini- mal graph
Citation (ISO format)
LUBOTZKY, Alexander, SMIRNOVA-NAGNIBEDA, Tatiana. Not Every Uniform Tree Covers Ramanujan Graphs. In: Journal of combinatorial theory. Series B, 1998, vol. 74, n° 2, p. 202–212. doi: 10.1006/jctb.1998.1843
Main files (1)
Article (Published version)
accessLevelRestricted
Identifiers
Journal ISSN0095-8956
844views
0downloads

Technical informations

Creation11/11/2010 14:21:00
First validation11/11/2010 14:21:00
Update time14/03/2023 16:08:45
Status update14/03/2023 16:08:44
Last indexation29/10/2024 17:23:23
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack