# neighbourhood

## Seymour's Second Neighbourhood Conjecture ★★★

Author(s): Seymour

**Conjecture**Any oriented graph has a vertex whose outdegree is at most its second outdegree.

Keywords: Caccetta-Häggkvist; neighbourhood; second; Seymour

Author(s): Seymour

Keywords: Caccetta-Häggkvist; neighbourhood; second; Seymour

- Subject
- Algebra (7)
- Analysis (5)
- Combinatorics (36)
- Geometry (29)
- Graph Theory (226)
- Group Theory (5)
- Logic (10)
- Number Theory (48)
- Theoretical Comp. Sci. (13)
- Topology (40)
- Unsorted (1)

- Author index
- Keyword index