Mimimum Degree and the Number of Chords

Jan Kara1, Daniel Kral2
1Department of Applied Mathematics, Charles University, Malostranské ndm. 25, 118 00 Prague, Czech Republic,
2Department of Applied Mathematics and Institute for ‘Theoretical Computer Sci- ence (Project LNOQOA056 supported by the Ministry of Education of Czech Republic), Charles University, Malostranské ndm. 25, 118 00 Prague, Czech Republic

Abstract

We address the following problem: What minimum degree forces a graph on \(n\) vertices to have a cycle with at least \(c\) chords? We prove that any graph with minimum degree \(\delta\) has a cycle with at least \(\frac{(\delta+1)(\delta-2)}{2}\) chords. We investigate asymptotic behaviour for large \(n\) and \(c\) and we consider the special case where \(n = c\).