Results 21 to 30 of about 1,423 (126)
When Is a Graded Free Complex Exact?
Mathematics, 2022 Minimal free resolutions of a finitely generated module over a polynomial ring S=k[x], with variables x={x1,…,xn} and a field k have been extensively studied.
David C. Molano +2 more
doaj +1 more source
Characterization of Graphs with an Eigenvalue of Large Multiplicity
Advances in Mathematical Physics, Volume 2020, Issue 1, 2020., 2020 Let G be a simple and undirected graph. The eigenvalues of the adjacency matrix of G are called the eigenvalues of G. In this paper, we characterize all the n‐vertex graphs with some eigenvalue of multiplicity n − 2 and n − 3, respectively. Moreover, as an application of the main result, we present a family of nonregular graphs with four distinct ...
Linming Qi +4 more
wiley +1 more source
Independent Set Reconfiguration in Cographs [PDF]
, 2014 We study the following independent set reconfiguration problem, called TAR-Reachability: given two independent sets $I$ and $J$ of a graph $G$, both of size at least $k$, is it possible to transform $I$ into $J$ by adding and removing vertices one-by-one,
AE Mouawad +21 more
core +2 more sources
Finite groups whose coprime graph is split, threshold, chordal, or a cograph [PDF]
Proceedings of the Estonian Academy of SciencesGiven a finite group G, the coprime graph of G, denoted by Î(G), is defined as an undirected graph with the vertex set G, and for distinct x, y â G, x is adjacent to y if and only if (o(x), o(y)) = 1, where o(x) and o(y) are the orders of x and y ...
Jin Chen, Shixun Lin, Xuanlong Ma
doaj +1 more source
On perfect and quasiperfect dominations in graphs [PDF]
, 2017 A subset S ¿ V in a graph G = ( V , E ) is a k -quasiperfect dominating set (for k = 1) if every vertex not in S is adjacent to at least one and at most k vertices in S .
Cáceres, José +4 more
core +2 more sources
$2$-polarity and algorithmic aspects of polarity variants on cograph superclasses [PDF]
Discrete Mathematics & Theoretical Computer ScienceA graph $G$ is said to be an $(s, k)$-polar graph if its vertex set admits a partition $(A, B)$ such that $A$ and $B$ induce, respectively, a complete $s$-partite graph and the disjoint union of at most $k$ complete graphs.
Fernando Esteban Contreras-Mendoza +1 more
doaj +1 more source
Contraction blockers for graphs with forbidden induced paths. [PDF]
, 2015 We consider the following problem: can a certain graph parameter of some given graph be reduced by at least d for some integer d via at most k edge contractions for some given integer k?
Diner, Öznur Yaşar +4 more
core +5 more sources
Defining and identifying cograph communities in complex networks
New Journal of Physics, 2015 Community or module detection is a fundamental problem in complex networks. Most of the traditional algorithms available focus only on vertices in a subgraph that are densely connected among themselves while being loosely connected to the vertices ...
Songwei Jia +6 more
doaj +1 more source
Cograph Regularized Collective Nonnegative Matrix Factorization for Multilabel Image Annotation
IEEE Access, 2019 Automatic image annotation is an effective and straightforward way to facilitate many applications in computer vision. However, manually annotating images is a computation-expensive and labor-intensive task. To address these problems, this paper proposes
Juli Zhang +3 more
doaj +1 more source
, 2010 Many fixed-parameter tractable algorithms using a bounded search tree have been repeatedly improved, often by describing a larger number of branching rules involving an increasingly complex case analysis.
A. Cournier +17 more
core +1 more source