Results 11 to 20 of about 1,242,256 (73)

Returnability in complex directed networks (digraphs) [PDF]

, 2008
The concept of returnability is proposed for complex directed networks (digraphs). It can be seen as a generalization of the concept of reciprocity. Two measures of the returnability are introduced. We establish closed formulas for the calculation of the
Estrada, Ernesto, Estrada, E., Hatano, Naomichi, Hatano, N., Ernesto Estrada, Naomichi Hatano   +5 more
core   +4 more sources

Disjoint cycles of different lengths in graphs and digraphs [PDF]

, 2017
International audienceIn this paper, we study the question of finding a set of $k$ vertex-disjoint cycles (resp. directed cycles) of distinct lengths in a given graph (resp. digraph).
Harutyunyan, Ararat, Lichiardopol, Nicolas, Li, Binlong, Bensmail, Julien, Le, Ngoc Khang   +4 more
core   +8 more sources

A Note on Path Signed Digraphs [PDF]

, 2010
The concept of a line signed digraph is generalized to that of a path signed ...
S. Vijay, H. C. Savithri, P. Siva Kota Reddy, Savithri, H. C., Reddyy, P. Siva Kota, Vijayz, S.   +5 more
core   +1 more source

Signed domination numbers of directed graphs [PDF]

, 2005
summary:The concept of signed domination number of an undirected graph (introduced by J. E. Dunbar, S. T. Hedetniemi, M. A. Henning and P. J. Slater) is transferred to directed graphs. Exact values are found for particular types of tournaments.
Zelinka, Bohdan
core   +2 more sources

Smarandachely antipodal signed digraphs [PDF]

, 2010
For standard terminology and notion in digraph theory, we refer the reader to the classic text-books of Bondy and Murty [1] and Harary et al.[3]; the non-standard will be given in this paper as and when ...
Salestina, M. Ruby, Prashanthy , B., Reddy, P. Siva Kota, P. Siva Kota Reddy, M. Ruby Salestina, B. Prashanth   +5 more
core   +1 more source

Negation Switching Equivalence in Signed Graphs [PDF]

, 2010
Unless mentioned or defined otherwise, for all terminology and notion in graph theory the reader is refer to [8].
Reddy, Siva Kota
core   +1 more source

Embedding problems in graphs and hypergraphs [PDF]

, 2011
The first part of this thesis concerns perfect matchings and their generalisations. We determine the minimum vertex degree that ensures a perfect matching in a 3-uniform hypergraph, thereby answering a question of Hàn, Person and Schacht.
Treglown, Andrew Clark
core   +7 more sources

A 9/4-Approximation for Directed Feedback Vertex Sets in Quasi-Transitive Digraphs [PDF]

We provide the first non-trivial approximation algorithm for the fundamental directed feedback vertex set (DFVS) problem in the class of quasi-transitive digraphs.
Mnich, Matthias, Ghorbani, Ebrahim
core   +2 more sources

On Tournament Inversion

Journal of Graph Theory, Volume 110, Issue 1, Page 82-91, September 2025.
ABSTRACT An inversion of a tournament T is obtained by reversing the direction of all edges with both endpoints in some set of vertices. Let inv k ( T ) be the minimum length of a sequence of inversions using sets of size at most k that result in the transitive tournament.
Raphael Yuster
wiley   +1 more source

Edge‐arc‐disjoint paths in semicomplete mixed graphs

Journal of Graph Theory, Volume 108, Issue 4, Page 705-721, April 2025.
Abstract The so‐called weak‐2‐linkage problem asks for a given digraph D=(V,A) $D=(V,A)$ and distinct vertices s1,s2,t1,t2 ${s}_{1},{s}_{2},{t}_{1},{t}_{2}$ of D $D$ whether D $D$ has arc‐disjoint paths P1,P2 ${P}_{1},{P}_{2}$ so that Pi ${P}_{i}$ is an (si,ti) $({s}_{i},{t}_{i})$‐path for i=1,2 $i=1,2$. This problem is NP‐complete for general digraphs
J. Bang‐Jensen, Y. Wang
wiley   +1 more source