Title
Two proofs of Bermond-Thomassen conjecture for regular tournaments
Abstract
Bermond-Thomassen conjecture says that a digraph of minimum out-degree at least 2r−1, r⩾1, contains at least r vertex-disjoint directed cycles. Thomassen proved that it is true when r=2, but it is still open for larger values of r, even when restricted to (regular) tournaments. In this paper, we present two proofs of this conjecture for regular tournaments. In the first one, we shall prove auxiliary results about union of sets contained in other union of sets, that might be of independent interest. The second one uses a more graph-theoretical approach, by studying the properties of a maximum set of vertex-disjoint directed triangles.
Year
DOI
Venue
2007
10.1016/j.endm.2007.01.008
Electronic Notes in Discrete Mathematics
Keywords
Field
DocType
digraph,circuit,tournament,Bermond-Thomassen conjecture,cycle
Discrete mathematics,Combinatorics,Mathematical proof,Conjecture,Mathematics,Digraph
Journal
Volume
ISSN
Citations 
28
1571-0653
2
PageRank 
References 
Authors
0.66
3
3
Name
Order
Citations
PageRank
Stéphane Bessy111719.68
Nicolas Lichiardopol2459.19
Jean-Sébastien Sereni326928.69