Remarks on the second neighborhood problem
نویسندگان
چکیده
The second neighborhood conjecture of Seymour asserts that for any orientation G = (V,E), there exists a vertex v ∈ V so that |N(v)| ≤ |N(v)|. The conjecture was resolved by Fisher for tournaments. In this paper we prove the second neighborhood conjecture for several additional classes of dense orientations. We also prove some approximation results, and reduce an asymptotic version of the conjecture to a finite case.
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عنوان ژورنال:
- Journal of Graph Theory
دوره 55 شماره
صفحات -
تاریخ انتشار 2007