Results 61 to 70 of about 891,390 (207)

Sharp thresholds for constraint satisfaction problems and homomorphisms

open access: yes, 2008
We determine under which conditions certain natural models of random constraint satisfaction problems have sharp thresholds of satisfiability. These models include graph and hypergraph homomorphism, the $(d,k,t)$-model, and binary constraint satisfaction
Hatami, Hamed, Molloy, Michael
core   +2 more sources

Recognizing Trees From Incomplete Decks

open access: yesJournal of Graph Theory, Volume 110, Issue 3, Page 322-336, November 2025.
ABSTRACT Given a graph G, the unlabeled subgraphs G − v are called the cards of G. The deck of G is the multiset { G − v : v ∈ V ( G ) }. Wendy Myrvold showed that a disconnected graph and a connected graph both on n vertices have at most ⌊ n 2 ⌋ + 1 cards in common and found (infinite) families of trees and disconnected forests for which this upper ...
Gabriëlle Zwaneveld
wiley   +1 more source

The Moran Process on a Random Graph

open access: yesRandom Structures &Algorithms, Volume 66, Issue 3, May 2025.
ABSTRACT We study the fixation probability for two versions of the Moran process on the random graph Gn,p$$ {G}_{n,p} $$ at the threshold for connectivity. The Moran process models the spread of a mutant population in a network. Throughout the process, there are vertices of two types, mutants, and non‐mutants.
Alan Frieze, Wesley Pegden
wiley   +1 more source

On the Laplacian Coefficients and Laplacian-Like Energy of Unicyclic Graphs with n Vertices and m Pendent Vertices

open access: yesJournal of Applied Mathematics, 2012
Let Φ(G,λ)=det(λIn-L(G))=∑k=0n(-1)kck(G)λn-k be the characteristic polynomial of the Laplacian matrix of a graph G of order n. In this paper, we give four transforms on graphs that decrease all Laplacian coefficients ck(G) and investigate a conjecture A.
Xinying Pai, Sanyang Liu
doaj   +1 more source

A survey and a new class of graceful unicylic graphs

open access: yesAKCE International Journal of Graphs and Combinatorics, 2020
A graph G admits a graceful labeling if there is a one-to-one map f from the set of vertices of G to such that when an edge xy is assigned the label the resulting set of edge labels is When such a labeling exists, G is called graceful. Rosa showed that a
Max Pambe Biatch’   +2 more
doaj   +1 more source

Eccentric connectivity index [PDF]

open access: yes, 2010
The eccentric connectivity index $\xi^c$ is a novel distance--based molecular structure descriptor that was recently used for mathematical modeling of biological activities of diverse nature. It is defined as $\xi^c (G) = \sum_{v \in V (G)} deg (v) \cdot
Ilić, Aleksandar
core  

Problems on Matchings and Independent Sets of a Graph

open access: yes, 2018
Let $G$ be a finite simple graph. For $X \subset V(G)$, the difference of $X$, $d(X) := |X| - |N (X)|$ where $N(X)$ is the neighborhood of $X$ and $\max \, \{d(X):X\subset V(G)\}$ is called the critical difference of $G$. $X$ is called a critical set if $
Bhattacharya, Amitava   +2 more
core   +1 more source

Edge colouring line graphs of unicyclic graphs

open access: yesDiscrete Applied Mathematics, 1992
A characterization of line graphs of unicyclic graphs is established, and it is proved that the line graph \(G\) of a unicyclic graph is in class 1 unless \(G\) is an odd cycle and an optimal edge colouring of the line graph of a unicyclic graph can be computed in time \(O(| E|)\) (note that the chromatic index problem is known to be \(NP\)-complete ...
Cai, Leizhen, Ellis, John A.
openaire   +1 more source

Selection of an Optimal Warehouses Using Global Regular Domination in Graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2025, Issue 1, 2025.
Let G = (V, E) be a simple graph. A subset S of V (G) is said to be global dominating set if S is a dominating set of the given graph G and its complement G. A subset whose induced subgraph is regular in G is also regular in G. A dominating set D of V (G) is called a regular dominating set if hSi is regular. In this article, we introduce global regular
R. Sundareswaran   +6 more
wiley   +1 more source

On degree-based graph invariants of fixed-order unicyclic graphs with prescribed maximum degree

open access: yesAIMS Mathematics
Consider a graph $ G $ having edge set $ E $, and denote by $ d_x $ the degree of a vertex $ x $ in $ G $. A unicyclic graph is defined as a connected graph containing exactly one cycle. This work focuses on unicyclic graphs of a fixed order and examines
Akbar Ali   +3 more
doaj   +1 more source

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