Zobrazeno 1 - 10
of 16
pro vyhledávání: '"05C21, 05C22"'
We study the problem of finding homomorphisms into odd cycles from planar graphs with high odd-girth. The Jaeger-Zhang conjecture states that every planar graph of odd-girth at least $4k+1$ admits a homomorphism to the odd cycle $C_{2k+1}$. The $k=1$
Externí odkaz:
http://arxiv.org/abs/2402.02689
Autor:
Bubboloni, Daniela, Gori, Michele
We consider the number of paths that must pass through a subset $X$ of vertices of a network $N$ in a maximum sequence of arc-disjoint paths connecting two vertices $y$ and $z$. We show that when $X$ is a singleton, that number equals the difference
Externí odkaz:
http://arxiv.org/abs/2003.13338
Autor:
Qian, Jianguo
In contrast to ordinary graphs, the number of the nowhere-zero group-flows in a signed graph may vary with different groups, even if the groups have the same order. In fact, for a signed graph $G$ and non-negative integer $d$, it was shown that there
Externí odkaz:
http://arxiv.org/abs/1805.07878
Tutte initiated the study of nowhere-zero flows and proved the following fundamental theorem: For every graph $G$ there is a polynomial $f$ so that for every abelian group $\Gamma$ of order $n$, the number of nowhere-zero $\Gamma$-flows in $G$ is $f(
Externí odkaz:
http://arxiv.org/abs/1701.07369
Autor:
Bubboloni, Daniela, Gori, Michele
In this paper we propose an in-depth analysis of a method, called the flow network method, which associates with any network a complete and quasi-transitive binary relation on its vertices. Such a method, originally proposed by Gvozdik (1987), is bas
Externí odkaz:
http://arxiv.org/abs/1606.03898
Autor:
Yang, Fan, Zhou, Sanming
A signed graph is a graph with a positive or negative sign on each edge. Regarding each edge as two half edges, an orientation of a signed graph is an assignment of a direction to each of its half edges such that the two half edges of a positive edge
Externí odkaz:
http://arxiv.org/abs/1508.04620
Autor:
Riaza, Ricardo
This paper addresses analytical aspects of deterministic, continuous-time dynamical systems defined on networks. The goal is to model and analyze certain phenomena which must be framed beyond the context of networked dynamical systems, understood as
Externí odkaz:
http://arxiv.org/abs/1501.01904
Autor:
Schubert, Michael, Steffen, Eckhard
Publikováno v:
European Journal of Combinatorics 48 (2015) 34-47
We study the flow spectrum ${\cal S}(G)$ and the integer flow spectrum $\overline{{\cal S}}(G)$ of signed $(2t+1)$-regular graphs. We show that if $r \in {\cal S}(G)$, then $r = 2+\frac{1}{t}$ or $r \geq 2 + \frac{2}{2t-1}$. Furthermore, $2 + \frac{1
Externí odkaz:
http://arxiv.org/abs/1307.1562
Autor:
Cardon, David A., Nielsen, Pace P.
Publikováno v:
Linear Algebra and its Applications, Volume 436, Issue 7, Pages 2187-2200, 2012
Using the relationship between totally nonnegative matrices and directed acyclic weighted planar networks, we show that $2\times 2$ minors of minor matrices of totally nonnegative matrices are also nonnegative. We give a combinatorial interpretation
Externí odkaz:
http://arxiv.org/abs/1101.1458
Autor:
Michele Gori, Daniela Bubboloni
Publikováno v:
Networks. 80:216-234
We consider the number of paths that must pass through a subset $X$ of vertices of a network $N$ in a maximum sequence of arc-disjoint paths connecting two vertices $y$ and $z$. We show that when $X$ is a singleton, that number equals the difference
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b53930d60295f550fd041f0f6496da4c
https://doi.org/10.1002/net.22088
https://doi.org/10.1002/net.22088
