Results 11 to 20 of about 44 (43)

A Finite Characterization and Recognition of Intersection Graphs of Hypergraphs with Rank at Most 3 and Multiplicity at Most 2 in the Class of Threshold Graphs [PDF]

open access: yesDiscussiones Mathematicae Graph Theory, 2017
We characterize the class L32$L_3^2 $ of intersection graphs of hypergraphs with rank at most 3 and multiplicity at most 2 by means of a finite list of forbidden induced subgraphs in the class of threshold graphs.
Metelsky Yury   +2 more
doaj   +2 more sources

Graphs of Linear Growth have Bounded Treewidth

open access: yes, 2023
A graph class G has linear growth if, for each graph G ∈ G and every positive integer r, every subgraph of G with radius at most r contains O(r) vertices. In this paper, we show that every graph class with linear growth has bounded treewidth. Mathematics
David Wood   +12 more
core   +1 more source

Mathematics Subject Classification interrater agreement dataset

open access: yes, 2022
The Mathematics Subject Classification organizes Publications, Software, and Research Data into a hierarchical classification scheme maintained by MathSciNet (mr) and zbMATH Open (zbmath). According to the classification scheme, both organizations mr and
Olaf Teschke   +2 more
core   +1 more source

Old and new generalizations of line graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 29, Page 1509-1521, 2004., 2004
Line graphs have been studied for over seventy years. In 1932, H. Whitney showed that for connected graphs, edge‐isomorphism implies isomorphism except for K3 and K1,3. The line graph transformation is one of the most widely studied of all graph transformations.
Jay Bagga
wiley   +1 more source

Homomorphic Preimages of Geometric Paths

open access: yesDiscussiones Mathematicae Graph Theory, 2018
A graph G is a homomorphic preimage of another graph H, or equivalently G is H-colorable, if there exists a graph homomorphism f : G → H. A geometric graph Ḡ is a simple graph G together with a straight line drawing of G in the plane with the vertices in
Cockburn Sally
doaj   +1 more source

A Note on the Crossing Numbers of 5-Regular Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2020
The crossing number cr(G) of a graph G is the smallest number of edge crossings in any drawing of G. In this paper, we prove that there exists a unique 5-regular graph G on 10 vertices with cr(G) = 2.
Ouyang Zhangdong
doaj   +1 more source

Requiring that Minimal Separators Induce Complete Multipartite Subgraphs

open access: yesDiscussiones Mathematicae Graph Theory, 2018
Complete multipartite graphs range from complete graphs (with every partite set a singleton) to edgeless graphs (with a unique partite set). Requiring minimal separators to all induce one or the other of these extremes characterizes, respectively, the ...
McKee Terry A.
doaj   +1 more source

On An Extremal Problem In The Class Of Bipartite 1-Planar Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2016
A graph G = (V, E) is called 1-planar if it admits a drawing in the plane such that each edge is crossed at most once. In this paper, we study bipartite 1-planar graphs with prescribed numbers of vertices in partite sets.
Czap Július   +2 more
doaj   +1 more source

The Crossing Number of The Hexagonal Graph H3,n

open access: yesDiscussiones Mathematicae Graph Theory, 2019
In [C. Thomassen, Tilings of the torus and the Klein bottle and vertex-transitive graphs on a fixed surface, Trans. Amer. Math. Soc. 323 (1991) 605–635], Thomassen described completely all (except finitely many) regular tilings of the torus S1 and the ...
Wang Jing   +2 more
doaj   +1 more source

Sharp Upper Bounds on the Clar Number of Fullerene Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2018
The Clar number of a fullerene graph with n vertices is bounded above by ⌊n/6⌋ − 2 and this bound has been improved to ⌊n/6⌋ − 3 when n is congruent to 2 modulo 6.
Gao Yang, Zhang Heping
doaj   +1 more source

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