منابع مشابه
Remarks on hamiltonian digraphs
An oriented graph is an out-tournament if the out-neighbourhood of every vertex is a tournament. This note is motivated by A. Kemnitz and B. Greger, Congr. Numer. 130 (1998) 127-131. We show that the main result of the paper by Kemnitz and Greger is an easy consequence of the characterization of hamiltonian out-tournaments by Bang-Jensen, Huang and Prisner, J. Combin. Theory Ser. B 59 (1993) 26...
متن کاملHamiltonian degree sequences in digraphs
We show that for each η > 0 every digraph G of sufficiently large order n is Hamiltonian if its outand indegree sequences d+1 ≤ · · · ≤ d + n and d−1 ≤ · · · ≤ d − n satisfy (i) d + i ≥ i+ ηn or d − n−i−ηn ≥ n− i and (ii) d − i ≥ i+ ηn or d+n−i−ηn ≥ n− i for all i < n/2. This gives an approximate solution to a problem of Nash-Williams [22] concerning a digraph analogue of Chvátal’s theorem. In ...
متن کاملCompetition Graphs of Hamiltonian Digraphs
K. F. Fraughnaugh et al. proved that a graph G is the competition graph of a hamiltonian digraph possibly having loops if and only if G has an edge clique cover C = {C1, . . . , Cn} that has a system of distinct representatives. [SIAM J. Discrete Math., 8 (1995), pp. 179–185]. We settle a question left open by their work, by showing that the words “possibly having loops” may be removed.
متن کاملOrientations of hamiltonian cycles in large digraphs
We prove that, with some exceptions, every digraph with n 3 9 vertices and at least ( n 1) (n 2) + 2 arcs contains all orientations of a Hamiltonian cycle.
متن کاملHamiltonian-colored powers of strong digraphs
For a strong oriented graph D of order n and diameter d and an integer k with 1 ≤ k ≤ d, the kth power D of D is that digraph having vertex set V (D) with the property that (u, v) is an arc of D if the directed distance ~ dD(u, v) from u to v in D is at most k. For every strong digraph D of order n ≥ 2 and every integer k ≥ ⌈n/2⌉, the digraph D is Hamiltonian and the lower bound ⌈n/2⌉ is sharp....
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Fundamenta Mathematicae
سال: 1969
ISSN: 0016-2736,1730-6329
DOI: 10.4064/fm-65-2-223-226