Results 61 to 70 of about 886,125 (210)

On the Relationships between Zero Forcing Numbers and Certain Graph Coverings

open access: yesSpecial Matrices, 2014
The zero forcing number and the positive zero forcing number of a graph are two graph parameters that arise from two types of graph colourings. The zero forcing number is an upper bound on the minimum number of induced paths in the graph that cover all ...
Taklimi Fatemeh Alinaghipour   +2 more
doaj   +1 more source

Strong Oriented Chromatic Number of Planar Graphs without Short Cycles [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2008
Let M be an additive abelian group. An M-strong-oriented coloring of an oriented graph G is a mapping f from V(G) to M such that f(u) j(v) whenever uv is an arc in G and f(v)−f(u) −(f(t)−f(z)) whenever uv and zt are two arcs in G.
Mickael Montassier   +2 more
doaj   +1 more source

(2,1)-Total labelling of outerplanar graphs

open access: yesDiscrete Applied Mathematics, 2007
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Chen, Dong, Wang, Weifan
openaire   +1 more source

Tight Distance Query Reconstruction for Trees and Graphs Without Long Induced Cycles

open access: yesRandom Structures &Algorithms, Volume 66, Issue 4, July 2025.
ABSTRACT Given access to the vertex set V$$ V $$ of a connected graph G=(V,E)$$ G=\left(V,E\right) $$ and an oracle that given two vertices u,v∈V$$ u,v\in V $$, returns the shortest path distance between u$$ u $$ and v$$ v $$, how many queries are needed to reconstruct E$$ E $$?
Paul Bastide, Carla Groenland
wiley   +1 more source

Feedback Arc Number and Feedback Vertex Number of Cartesian Product of Directed Cycles

open access: yesDiscrete Dynamics in Nature and Society, Volume 2019, Issue 1, 2019., 2019
For a digraph D, the feedback vertex number τ(D), (resp. the feedback arc number τ′(D)) is the minimum number of vertices, (resp. arcs) whose removal leaves the resultant digraph free of directed cycles. In this note, we determine τ(D) and τ′(D) for the Cartesian product of directed cycles D=Cn1→□Cn2→□…Cnk→. Actually, it is shown that τ′D=n1n2…nk∑i=1k1/
Xiaohong Chen   +2 more
wiley   +1 more source

Track Layouts of Graphs [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2004
A \emph(k,t)-track layout of a graph G consists of a (proper) vertex t-colouring of G, a total order of each vertex colour class, and a (non-proper) edge k-colouring such that between each pair of colour classes no two monochromatic edges cross.
Vida Dujmović   +2 more
doaj   +3 more sources

A graph and its complement with specified properties I: connectivity

open access: yesInternational Journal of Mathematics and Mathematical Sciences, 1979
We investigate the conditions under which both a graph G and its complement G¯ possess a specified property. In particular, we characterize all graphs G for which G and G¯ both (a) have connectivity one, (b) have line-connectivity one, (c) are 2 ...
Jin Akiyama, Frank Harary
doaj   +1 more source

L(h,1,1)-Labeling of Outerplanar Graphs [PDF]

open access: yesMathematical Methods of Operations Research, 2006
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
CALAMONERI, Tiziana   +3 more
openaire   +11 more sources

On vertex‐transitive graphs with a unique hamiltonian cycle

open access: yesJournal of Graph Theory, Volume 108, Issue 1, Page 65-99, January 2025.
Abstract A graph is said to be uniquely hamiltonian if it has a unique hamiltonian cycle. For a natural extension of this concept to infinite graphs, we find all uniquely hamiltonian vertex‐transitive graphs with finitely many ends, and also discuss some examples with infinitely many ends.
Babak Miraftab, Dave Witte Morris
wiley   +1 more source

On the Hub Number of Ring Graphs and Their Behavior Under Graph Operations

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2025, Issue 1, 2025.
This study examines the hub number of ring graphs and investigates their behavior under operations such as union, intersection, and join. Different findings for this parameter are found for a variety of types of ring graphs, such as commutative ring graphs, path ring graphs, complete ring graphs, cycle ring graphs, and star ring graphs, for which the ...
Mohammed Alsharafi   +3 more
wiley   +1 more source

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