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An extremal problem on potentially K_p,1,1-graphic sequences [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2005
A sequence S is potentially K_p,1,1 graphical if it has a realization containing a K_p,1,1 as a subgraph, where K_p,1,1 is a complete 3-partite graph with partition sizes p,1,1.
Chunhui Lai
doaj   +1 more source

Solutions to problems about potentially Ks,t-bigraphic pair

open access: yesOpen Mathematics, 2022
Let S=(a1,…,am;b1,…,bn)S=\left({a}_{1},\ldots ,{a}_{m};\hspace{0.33em}{b}_{1},\ldots ,{b}_{n}), where a1,…,am{a}_{1},\ldots ,{a}_{m} and b1,…,bn{b}_{1},\ldots ,{b}_{n} are two nonincreasing sequences of nonnegative integers. The pair S=(a1,…,am;b1,…,bn)S=
Yin Jian-Hua, Zhang Liang
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The Minimum Size of a Graph with Given Tree Connectivity

open access: yesDiscussiones Mathematicae Graph Theory, 2021
For a graph G = (V, E) and a set S ⊆ V of at least two vertices, an S-tree is a such subgraph T of G that is a tree with S ⊆ V (T). Two S-trees T1 and T2 are said to be internally disjoint if E(T1) ∩ E(T2) = ∅ and V (T1) ∩ V (T2) = S, and edge-disjoint ...
Sun Yuefang, Sheng Bin, Jin Zemin
doaj   +1 more source

THE EXACT MINIMUM NUMBER OF TRIANGLES IN GRAPHS WITH GIVEN ORDER AND SIZE

open access: yesForum of Mathematics, Pi, 2020
What is the minimum number of triangles in a graph of given order and size? Motivated by earlier results of Mantel and Turán, Rademacher solved the first nontrivial case of this problem in 1941.
HONG LIU   +2 more
doaj   +1 more source

Hereditary Equality of Domination and Exponential Domination in Subcubic Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
Let γ(G) and γe(G) denote the domination number and exponential domination number of graph G, respectively. Henning et al., in [Hereditary equality of domination and exponential domination, Discuss. Math. Graph Theory 38 (2018) 275–285] gave a conjecture:
Chen Xue-Gang, Wang Yu-Feng, Wu Xiao-Fei
doaj   +1 more source

Capture-Time Extremal Cop-Win Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
We investigate extremal graphs related to the game of Cops and Robbers. We focus on graphs where a single cop can catch the robber; such graphs are called cop-win.
Offner David, Ojakian Kerry
doaj   +1 more source

Banhatti, revan and hyper-indices of silicon carbide Si2C3-III[n,m]

open access: yesOpen Chemistry, 2021
In recent years, several structure-based properties of the molecular graphs are understood through the chemical graph theory. The molecular graph GG of a molecule consists of vertices and edges, where vertices represent the atoms in a molecule and edges ...
Zhao Dongming   +6 more
doaj   +1 more source

Comparing Eccentricity-Based Graph Invariants

open access: yesDiscussiones Mathematicae Graph Theory, 2020
The first and second Zagreb eccentricity indices (EM1 and EM2), the eccentric distance sum (EDS), and the connective eccentricity index (CEI) are all recently conceived eccentricity-based graph invariants, some of which found applications in chemistry ...
Hua Hongbo, Wang Hongzhuan, Gutman Ivan
doaj   +1 more source

The Turán Number for 4 · Sℓ1

open access: yesDiscussiones Mathematicae Graph Theory, 2022
The Turán number of a graph H, denoted by ex(n, H), is the maximum number of edges of an n-vertex simple graph having no H as a subgraph. Let Sℓ denote the star on ℓ + 1 vertices, and let k · Sℓ denote k disjoint copies of Sℓ. Erdős and Gallai determined
Li Sha-Sha, Yin Jian-Hua, Li Jia-Yun
doaj   +1 more source

A Note on Packing of Uniform Hypergraphs

open access: yesDiscussiones Mathematicae Graph Theory, 2022
We say that two n-vertex hypergraphs H1 and H2 pack if they can be found as edge-disjoint subhypergraphs of the complete hypergraph Kn. Whilst the problem of packing of graphs (i.e., 2-uniform hypergraphs) has been studied extensively since seventies ...
Konarski Jerzy   +2 more
doaj   +1 more source

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