Results 21 to 30 of about 468 (68)

Graph Exponentiation and Neighborhood Reconstruction

open access: yesDiscussiones Mathematicae Graph Theory, 2021
Any graph G admits a neighborhood multiset 𝒩(G) = {NG(x) | x ∈ V (G)} whose elements are precisely the open neighborhoods of G. We say G is neighborhood reconstructible if it can be reconstructed from 𝒩(G), that is, if G ≅ H whenever 𝒩 (G) = 𝒩(H) for ...
Hammack Richard H.
doaj   +1 more source

On the Connectivity of Token Graphs of Trees [PDF]

open access: yesDiscrete Mathematics & Theoretical Computer Science, 2022
Let $k$ and $n$ be integers such that $1\leq k \leq n-1$, and let $G$ be a simple graph of order $n$. The $k$-token graph $F_k(G)$ of $G$ is the graph whose vertices are the $k$-subsets of $V(G)$, where two vertices are adjacent in $F_k(G)$ whenever ...
Ruy Fabila-Monroy   +2 more
doaj   +1 more source

The General Position Problem on Kneser Graphs and on Some Graph Operations

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A vertex subset S of a graph G is a general position set of G if no vertex of S lies on a geodesic between two other vertices of S. The cardinality of a largest general position set of G is the general position number (gp-number) gp(G) of G.
Ghorbani Modjtaba   +5 more
doaj   +1 more source

Subgroups of arbitrary even ordinary depth

open access: yes, 2020
We show that for each positive integer $n$, there are a group $G$ and a subgroup $H$ such that the ordinary depth is $d(H, G) = 2n$. This solves the open problem posed by Lars Kadison whether even ordinary depth larger than $6$ can occur.Comment: 9 pages;
Breuer, Thomas   +2 more
core   +1 more source

Structures of W(2.2) Lie conformal algebra

open access: yesOpen Mathematics, 2016
The purpose of this paper is to study W(2, 2) Lie conformal algebra, which has a free ℂ[∂]-basis {L, M} such that [LλL]=(∂+2λ)L,[LλM]=(∂+2λ)M,[MλM]=0$\begin{equation}[{L_\lambda }L] = (\partial + 2\lambda )L,[{L_\lambda }M] = (\partial + 2\lambda )M,[{M_\
Yuan Lamei, Wu Henan
doaj   +1 more source

Total Colourings of Direct Product Graphs

open access: yes, 2019
A graph is k-total colourable if there is an assignment of k different colours to the vertices and edges of the graph such that no two adjacent nor incident elements receive the same colour.
Janssen, Jeannette, MacKeigan, Kyle
core   +1 more source

Soft covering based rough graphs and corresponding decision making

open access: yesOpen Mathematics, 2019
Soft set theory and rough set theory are two new tools to discuss uncertainty. Graph theory is a nice way to depict certain information. Particularly soft graphs serve the purpose beautifully.
Park Choonkil   +5 more
doaj   +1 more source

The competition number of a generalized line graph is at most two

open access: yes, 2012
In 1982, Opsut showed that the competition number of a line graph is at most two and gave a necessary and sufficient condition for the competition number of a line graph being one.
Park, Boram, Sano, Yoshio
core   +3 more sources

Integral Laplacian graphs with a unique repeated Laplacian eigenvalue, I

open access: yesSpecial Matrices, 2023
The set Si,n={0,1,2,…,n−1,n}\{i}{S}_{i,n}=\left\{0,1,2,\ldots ,n-1,n\right\}\setminus \left\{i\right\}, 1⩽i⩽n1\leqslant i\leqslant n, is called Laplacian realizable if there exists an undirected simple graph whose Laplacian spectrum is Si,n{S}_{i,n}. The
Hameed Abdul, Tyaglov Mikhail
doaj   +1 more source

Path homology theory of edge-colored graphs

open access: yesOpen Mathematics, 2021
In this paper, we introduce the category and the homotopy category of edge-colored digraphs and construct the functorial homology theory on the foundation of the path homology theory provided by Grigoryan, Muranov, and Shing-Tung Yau.
Muranov Yuri V., Szczepkowska Anna
doaj   +1 more source

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