نتایج جستجو برای: oriented graph

تعداد نتایج: 322031  

Journal: :Transactions of the Association for Computational Linguistics 2019

Journal: :Symmetry 2022

The presented herb recommendation system aims to analyze the patients’ symptoms and recommends a set of herbs as prescription treat diseases. In addition symptoms, personal properties induced diagnoses are also essential for treatment making. Specifically, different age groups, treatments different. However, existing studies only use represent patients ignore multidimensional features modeling....

Journal: :ACM Transactions on Knowledge Discovery From Data 2021

Knowledge graph embedding, which aims at learning the low-dimensional representations of entities and relationships, has attracted considerable research efforts recently. However, most knowledge embedding methods focus on structural relationships in fixed triples while ignoring temporal information. Currently, existing time-aware only factual plausibility, smoothness, models interactions betwee...

2018
Fenglei TIAN Dein WONG

A mixed graph means a graph containing both oriented edges and undirected edges. The nullity of the Hermitian-adjacency matrix of a mixed graph G, denoted by ηH(G), is referred to as the multiplicity of the eigenvalue zero. In this paper, for a mixed unicyclic graph G with given order and matching number, we give a formula on ηH(G), which combines the cases of undirected and oriented unicyclic ...

Journal: :CoRR 2016
Pierre Aboulker Jørgen Bang-Jensen Nicolas Bousquet Pierre Charbit Frédéric Havet Frédéric Maffray José Zamora

A famous conjecture of Gyárfás and Sumner states for any tree T and integer k, if the chromatic number of a graph is large enough, either the graph contains a clique of size k or it contains T as an induced subgraph. We discuss some results and open problems about extensions of this conjecture to oriented graphs. We conjecture that for every oriented star S and integer k, if the chromatic numbe...

Journal: :Electr. J. Comb. 2011
Yaoping Hou Tiangang Lei

An oriented graph Gσ is a simple undirected graph G with an orientation, which assigns to each edge a direction so that Gσ becomes a directed graph. G is called the underlying graph of Gσ and we denote by S(Gσ) the skew-adjacency matrix of Gσ and its spectrum Sp(Gσ) is called the skew-spectrum of Gσ. In this paper, the coefficients of the characteristic polynomial of the skew-adjacency matrix S...

Journal: :Inf. Process. Lett. 1994
André Raspaud Éric Sopena

A k?coloring of an oriented graph G = (V; A) is an assignment c of one of the colors 1; 2; : : :; k to each vertex of the graph such that, for every arc (x; y) of G, c(x) 6 = c(y). The k?coloring is good if for every arc (x; y) of G there is no arc (z; t) 2 A such that c(x) = c(t) and c(y) = c(z). A k?coloring is said to be semi?strong if for every vertex x of G, c(z) 6 = c(t) for any pair fz; ...

Journal: :Discussiones Mathematicae Graph Theory 2015
Olivier Baudon Julien Bensmail Éric Sopena

The well-known 1-2-3 Conjecture addressed by Karoński, Luczak and Thomason asks whether the edges of every undirected graph G with no isolated edge can be assigned weights from {1, 2, 3} so that the sum of incident weights at each vertex yields a proper vertex-colouring of G. In this work, we consider a similar problem for oriented graphs. We show that the arcs of every oriented graph − → G can...

1980
J. C. ARDITTI H. A. JUNG

Let Kbe a set, finite or infinite. A simple directed graph P = {V, U) is said to be "transitively oriented" if the existence of a directed path from a vertex x to a vertex y implies the existence of an arc (x, y)e U. For undefined graph-theoretical terms see for instance [4]. A transitively oriented graph on the vertex set V is nothing but the graph of some partial ordering of the set V; loops ...

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