Abstract
It is known that every simple graph with n3 / 2 edges contains a 4-cycle. A similar statement for digraphs is not possible since no condition on the number of arcs can guarantee an (oriented) 4-cycle. We find a condition which does guarantee the presence of a 4-cycle and our result is tight. Our condition, which we call f-mixing, can be seen as a quasirandomness condition on the orientation of the digraph. We also investigate the notion of mixing for regular and almost regular digraphs. In particular we determine how mixing a random orientation of a random graph is.
| Original language | English |
|---|---|
| Pages (from-to) | 63-68 |
| Number of pages | 6 |
| Journal | Electronic Notes in Discrete Mathematics |
| Volume | 30 |
| Issue number | C |
| DOIs | |
| Publication status | Published - 20 Feb 2008 |
| Externally published | Yes |
Keywords
- digraphs
- oriented 4-cycles
- pseudo random digraphs