Results 131 to 140 of about 2,715,030 (252)

Signed total double Roman dominating functions in graphs

AKCE International Journal of Graphs and Combinatorics
A signed total double Roman dominating function (STDRDF) on an isolated-free graph [Formula: see text] is a function [Formula: see text] such that (i) every vertex v with [Formula: see text] has at least two neighbors assigned 2 under f or one neighbor w
L. Shahbazi, H. Abdollahzadeh Ahangar, S. M. Sheikholeslami   +2 more
doaj   +1 more source

Systematic Review of Parasite Diversity in Wild Freshwater Fishes and Their Host‐Locality Interactions in Türkiye

Zoologica Scripta, EarlyView.
ABSTRACT This systematic review documented a taxonomically diverse parasite fauna of freshwater fishes across seven geographical regions of Türkiye, encompassing 11 phyla: Acanthocephala, Annelida, Arthropoda, Choanozoa, Ciliophora, Cnidaria, Euglenozoa, Mollusca, Myzozoa, Nematoda, and Platyhelminthes.
Canan Hamurkaroğlu, Ahmet Özer, Nazan Danacıoğlu, Ayten Yiğiter   +3 more
wiley   +1 more source

Density Conditions for k Vertex‐Disjoint Triangles in Tripartite Graphs

Journal of Graph Theory, Volume 113, Issue 4, Page 634-649, December 2026.
ABSTRACT Let n , k be positive integers such that n ≥ k and G be a tripartite graph with parts A , B , C such that ∣ A ∣ = ∣ B ∣ = ∣ C ∣ = n. Denote the edge densities of G [ A , B ] , G [ A , C ] and G [ B , C ] by α , β and γ, respectively. In this paper, we study edge density conditions for the existence of k vertex‐disjoint triangles in a ...
Mingyang Guo, Klas Markström
wiley   +1 more source

Coloring Complete and Complete Bipartite Graphs from Random Lists

, 2016
Assign to each vertex v of the complete graph on n vertices a list L(v) of colors by choosing each list independently and uniformly at random from all f(n)-subsets of a color set , where f(n) is some integer-valued function of n. Such a list assignment L
Haggkvist, Roland, Haggkvist, Roland,, Casselgren, Carl Johan,, Casselgren, Carl Johan   +3 more
core   +1 more source

On Fork‐Free t‐Perfect Graphs

Journal of Graph Theory, Volume 113, Issue 4, Page 553-570, December 2026.
ABSTRACT In an effort to understand the complexity of the maximum independent set problem, Chvátal introduced t‐perfect graphs. While a full characterization of this class remains open, important progress has been made for claw‐free graphs [Bruhn and Stein, Math. Program. 2012] and P 5‐free graphs [Bruhn and Fuchs, SIAM J. Discrete Math. 2017]. We take
Yixin Cao, Shenghua Wang
wiley   +1 more source

Tree Independence Number III. Thetas, Prisms and Stars

Journal of Graph Theory, Volume 113, Issue 4, Page 619-633, December 2026.
ABSTRACT We prove that for every t ∈ N there exists τ = τ ( t ) ∈ N such that every (theta, prism, K 1 , t)‐free graph has tree independence number at most τ (where we allow “prisms” to have one path of length zero).
Maria Chudnovsky, Sepehr Hajebi, Nicolas Trotignon   +2 more
wiley   +1 more source

P2p-factorization of a complete bipartite graph

Discrete Mathematics, 1993
Given a graph \(G\), every spanning subgraph with all its components isomorphic to the \(2k\)-vertex path is called a \(P_{2k}\)-factor of \(G\), for a fixed integer \(k\geq 1\). It is shown that the complete bipartite graph \(K_{n,m}\) is the edge-disjoint union of \(P_{2k}\)-factors if and only if \(m=n\) and \(m\equiv 0\mod{k(2k-1)}\).
openaire   +2 more sources

Stable Cuts, NAC‐Colourings and Flexible Realisations of Graphs

Journal of Graph Theory, Volume 113, Issue 3, Page 411-427, November 2026.
ABSTRACT A (2‐dimensional) realisation of a graph G is a pair ( G , p ), where p maps the vertices of G to R 2. A realisation is flexible if it can be continuously deformed while keeping the edge lengths fixed, and rigid otherwise. We say that G is rigid if every generic realisation of G is rigid; otherwise, G is flexible. In this paper, we investigate
Katie Clinch, Dániel Garamvölgyi, John Haslegrave, Tony Huynh, Jan Legerský, Anthony Nixon   +5 more
wiley   +1 more source

Linear Versus Centred Colouring via Pseudogrids

Journal of Graph Theory, Volume 113, Issue 3, Page 448-461, November 2026.
ABSTRACT A centred colouring of a graph is a vertex colouring in which every connected subgraph contains a vertex whose colour is unique and a linear colouring is a vertex colouring in which every (not‐necessarily induced) path contains a vertex whose colour is unique.
Prosenjit Bose, Vida Dujmović, Hussein Houdrouge, Mehrnoosh Javarsineh, Pat Morin   +4 more
wiley   +1 more source

A Min–Max Relation on Dicuts and Dijoins in Weighted Chordal Digraphs

Journal of Graph Theory, Volume 113, Issue 3, Page 462-469, November 2026.
ABSTRACT In a digraph, a dicut is a cut where all the arcs cross in one direction. A dijoin is a subset of arcs that intersects every dicut. Edmonds and Giles conjectured that in a weighted digraph, the minimum weight of a dicut is equal to the maximum size of a packing of dijoins. This has been disproved. However, the unweighted version conjectured by
Gérard Cornuéjols, Siyue Liu, R. Ravi
wiley   +1 more source