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Wyszukujesz frazę "hypergraph" wg kryterium: Temat


Tytuł:
The existence of bipartite almost self-complementary 3-uniform hypergraphs
Autorzy:
Kamble, L. N.
Deshpande, C. M.
Athawale, B. P.
Powiązania:
https://bibliotekanauki.pl/articles/29519545.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
almost self-complementary 3-uniform hypergraph
bipartite hypergraph
bipartite self-complementary 3-uniform hypergraph
bipartite almost self-complementary 3-uniform hypergraph
Opis:
An almost self-complementary 3-uniform hypergraph on n vertices exists if and only if n is congruent to 3 modulo 4. A hypergraph $ H $ with vertex set $ V $ and edge set $ E $ is called bipartite if $ V $ can be partitioned into two subsets $ V_1 $ and $ V_2 $ such that $ e ∩ V_1 ≠ ∅ $ and $e ∩ V_2 ≠ ∅ $ for any $ e ∈ E $. A bipartite self-complementary 3-uniform hypergraph $ H $ with partition $ (V_1, V_2) $ of the vertex set $ V $ such that $ |V_1| = m $ and $ |V_2| = n $ exists if and only if either (i) $ m = n $ or (ii) $ m ≠ n $ and either $ m $ or $ n $ is congruent to 0 modulo 4 or (iii) $ m ≠ n $ and both $ m $ and $ n $ are congruent to 1 or 2 modulo 4. In this paper we define a bipartite almost self-complementary 3-uniform hypergraph $ H $ with partition $ (V_1, V_2) $ of a vertex set $ V $ such that $ |V_1| = m $ and $ |V_2| = n $ and find the conditions on $ m $ and $ n $ for a bipartite 3-uniform hypergraph $ H $ to be almost self-complementary. We also prove the existence of bi-regular bipartite almost self-complementary 3-uniform hypergraphs.
Źródło:
Opuscula Mathematica; 2023, 43, 5; 663-673
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic Enumeration of Non-Uniform Linear Hypergraphs
Autorzy:
Hasheminezhad, Mahdieh
McKay, Brendan D.
Powiązania:
https://bibliotekanauki.pl/articles/32361742.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Steiner system
linear hypergraph
asymptotic enumeration
switching method
Opis:
A linear hypergraph, also known as a partial Steiner system, is a collection of subsets of a set such that no two of the subsets have more than one element in common. Most studies of linear hypergraphs consider only the uniform case, in which all the subsets have the same size. In this paper we provide, for the first time, asymptotically precise estimates of the number of linear hypergraphs in the non-uniform case, as a function of the number of subsets of each size.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 219-230
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrigendum to: Bounds on the Number of Edges of Edge-Minimal, Edge-Maximal and l -Hypertrees [Discussiones Mathematicae Graph Theory 36 (2016) 259–278]
Autorzy:
Szabó, Péter G.N.
Powiązania:
https://bibliotekanauki.pl/articles/32361734.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
hypertree
chain in hypergraph
edge-minimal hypertree
edge-maximal hypertree
2-hypertree
Steiner system
Opis:
In this corrigendum, we correct the proof of Theorem 10 from our paper titled „Bounds on the number of edges of edge-minimal, edge-maximal and l-hypertrees”.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 315-316
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Covering the Edges of a Random Hypergraph by Cliques
Autorzy:
Rödl, Vojtěch
Ruciński, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/32222535.pdf
Data publikacji:
2022-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
r-uniform random hypergraph
clique covering
Opis:
We determine the order of magnitude of the minimum clique cover of the edges of a binomial, r-uniform, random hypergraph G(r)(n, p), p fixed. In doing so, we combine the ideas from the proofs of the graph case (r = 2) in Frieze and Reed [Covering the edges of a random graph by cliques, Combinatorica 15 (1995) 489–497] and Guo, Patten, Warnke [Prague dimension of random graphs, manuscript submitted for publication].
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 4; 1333-1349
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cyclic Partitions of Complete and Almost Complete Uniform Hypergraphs
Autorzy:
Dilbarjot
Gosselin, Shonda Dueck
Powiązania:
https://bibliotekanauki.pl/articles/32305661.pdf
Data publikacji:
2022-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
almost self-complementary hypergraph
uniform hypergraph
cyclically t -complementary hypergraph
( t,k )-complementing permutation
Opis:
We consider cyclic partitions of the complete $k$-uniform hypergraph on a finite set $V$, minus a set of $s$ edges, $ s \ge 0 $. An $s$-almost $t$-complementary $k$-hypergraph is a $k$-uniform hypergraph with vertex set $V$ and edge set $E$ for which there exists a permutation $ \theta \in Sym(V)$ such that the sets $E$, $ E^\theta $, $ E^\{\theta^2} $, . . ., $ E^{\theta^{t−1}} $ partition the set of all $k$-subsets of $V$ minus a set of $s$ edges. Such a permutation $ \theta $ is called an $s$-almost $(t, k)$-complementing permutation. The $s$-almost $t$-complementary $k$-hypergraphs are a natural generalization of the almost self-complementary graphs which were previously studied by Clapham, Kamble et al. and Wojda. We prove the existence of an $s$-almost $ p^\alpha $-complementary $k$-hypergraph of order $n$, where $p$ is prime, \( s= \Pi_{i \ge 0 } \binom{n_i}{k_i} \), and $n_i$ and $k_i$ are the entries in the base-$ p^\alpha $ representations of $n$ and $k$, respectively. This existence result yields a combinatorial argument which generalizes Lucas’ classic 1878 number theory result to prime powers, which was originally proved by Davis and Webb in 1990 by another method. In addition, we prove an alternative statement of the necessary and sufficient conditions for the existence of a $ p^\alpha $-complementary $k$-hypergraph, and the equivalence of these two conditions yield an interesting relationship between the base-$p$ representation and the base-$ p^\alpha $ representation of a positive integer $n$. Finally, we determine a set of necessary and sufficient conditions on $n$ for the existence of a $t$-complementary $k$-uniform hypergraph on $n$ vertices for composite values of $t$, extending previous results due to Wojda, Szymański and Gosselin.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 3; 747-758
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High Girth Hypergraphs with Unavoidable Monochromatic or Rainbow Edges
Autorzy:
Axenovich, Maria
Karrer, Annette
Powiązania:
https://bibliotekanauki.pl/articles/32361723.pdf
Data publikacji:
2022-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
hypergraph
chromatic number
mixed hypergraph
bihyper-graphs
monochromatic
rainbow
girth
selective
Opis:
A classical result of Erdős and Hajnal claims that for any integers k, r, g ≥ 2 there is an r-uniform hypergraph of girth at least g with chromatic number at least k. This implies that there are sparse hypergraphs such that in any coloring of their vertices with at most k − 1 colors there is a monochromatic hyperedge. When there is no restriction on the number of the colors used, one can easily avoid monochromatic hyperedges. Then, however, so-called rainbow or multicolored hyperedges might appear. Nešetřil and Rödl [19] called hypergraphs such that in any vertex-coloring there is either a monochromatic or a rainbow hyperedge, selective. They showed an existence of selective r-uniform hypergraphs of girth g for any integers r, g ≥ 2 using probabilistic and explicit constructions. In this paper, we provide a slightly di erent construction of such hypergraphs and summarize the probabilistic approaches. The main building block of the construction, a part-rainbow-forced hypergraph, is of independent interest. This is an r-uniform r-partite hypergraph with a given girth such that in any vertex-coloring that is rainbow on each part, there is a rainbow hyperedge. We give a simple construction of such a hypergraph that does not use iterative amalgamation.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 2; 471-484
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Directed hypergraph observers-based qualitative fault monitoring tasks
Autorzy:
Garai, Dhaou
El Harabi, Rafika
Bacha, Faouzi
Powiązania:
https://bibliotekanauki.pl/articles/2096167.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
graphical modelling
directed hypergraph observer
fault monitoring
qualitative analysis
modelowanie graficzne
monitorowanie błędów
analiza jakościowa
Opis:
To create a precise model structure and perform fault monitoring algorithms for a wide range of complex systems along with dynamic behavioural characteristics, the causal graph-based methods were considered herein. In this paper, a new scheme was devised based on fast fault detection mechanism relying on the Directed Hypergraph Observer model. The performance of the suggested pattern is illustrated by a case study including systems with single energy. Noting that the modern methods possess a large range of applications for the reliability and energy effectiveness analysis related to multi-energy systems. The Directed Hypergraph model architecture was exploited to generate the diagnostic condition based on a graphical observer.
Źródło:
Diagnostyka; 2021, 22, 4; 67-76
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized Hypergraph Coloring
Autorzy:
Schweser, Thomas
Powiązania:
https://bibliotekanauki.pl/articles/32083810.pdf
Data publikacji:
2021-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
hypergraph decomposition
vertex partition
degeneracy
coloring of hypergraphs
hypergraph properties
Opis:
A smooth hypergraph property \(\mathcal{P}\) is a class of hypergraphs that is hereditary and non-trivial, i.e., closed under induced subhypergraphs and it contains a non-empty hypergraph but not all hypergraphs. In this paper we examine \(\mathcal{P}\)-colorings of hypergraphs with smooth hypergraph properties \(\mathcal{P}\). A \(\mathcal{P}\)-coloring of a hypergraph $H$ with color set $C$ is a function $\varphi : V(H) → C$ such that \(H\big[\varphi^{−1}(c)\big]\) belongs to \(\mathcal{P}\) for all $c ∈ C$. Let $L : V (H) → 2^C$ be a so called list-assignment of the hypergraph $H$. Then, a (\(\mathcal{P}, L\))-coloring of $H$ is a \(\mathcal{P}\)-coloring $\varphi$ of $H$ such that $\varphi(v) ∈ L(v)$ for all $v ∈ V (H)$. The aim of this paper is a characterization of (\(\mathcal{P}, L\))-critical hypergraphs. Those are hypergraphs $H$ such that $H − v$ is (\(\mathcal{P}, L\))-colorable for all $v ∈ V (H)$ but $H$ itself is not. Our main theorem is a Gallai-type result for critical hypergraphs, which implies a Brooks-type result for (\(\mathcal{P}, L\))-colorable hypergraphs. In the last section, we prove a Gallai-type bound for the degree sum of (\(\mathcal{P}, L\))-critical locally simple hypergraphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 1; 103-121
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Lagrangian Density of {123, 234, 456} and the Turán Number of its Extension
Autorzy:
Chen, Pingge
Liang, Jinhua
Peng, Yuejian
Powiązania:
https://bibliotekanauki.pl/articles/32222733.pdf
Data publikacji:
2021-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Turán number
hypergraph Lagrangian
Lagrangian density
Opis:
Given a positive integer $n$ and an $r$-uniform hypergraph $F$, the Turán number $ex(n, F)$ is the maximum number of edges in an $F$-free $r$-uniform hypergraph on $n$ vertices. The Turán density of $F$ is defined as \(π(F)=lim_{n→∞}\frac{ex(n,F)}{\binom{n}{r}}\). The Lagrangian density of $F$ is \(π_\lambda(F) = sup\{r!\lambda(G):G\) is \(F-free\}\), where $\lambda(G)$ is the Lagrangian of $G$. Sidorenko observed that \(π(F) ≤ π_\lambda(F)\), and Pikhurko observed that \(π(F) = π_\lambda(F)\) if every pair of vertices in $F$ is contained in an edge of $F$. Recently, Lagrangian densities of hypergraphs and Turán numbers of their extensions have been studied actively. For example, in the paper [A hypergraph Turán theorem via Lagrangians of intersecting families, J. Combin. Theory Ser. A 120 (2013) 2020–2038], Hefetz and Keevash studied the Lagrangian densitiy of the 3-uniform graph spanned by {123, 456} and the Turán number of its extension. In this paper, we show that the Lagrangian density of the 3-uniform graph spanned by {123, 234, 456} achieves only on $K_5^3$. Applying it, we get the Turán number of its extension, and show that the unique extremal hyper-graph is the balanced complete 5-partite 3-uniform hypergraph on $n$ vertices.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 4; 905-921
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2 × ℤ2 -Cordial Cycle-Free Hypergraphs
Autorzy:
Cichacz, Sylwia
Görlich, Agnieszka
Tuza, Zsolt
Powiązania:
https://bibliotekanauki.pl/articles/32361757.pdf
Data publikacji:
2021-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
V 4 -cordial graph
hypergraph
labeling of hypergraph
hyper-tree
Opis:
Hovey introduced A-cordial labelings as a generalization of cordial and harmonious labelings [7]. If A is an Abelian group, then a labeling f : V (G) → A of the vertices of some graph G induces an edge labeling on G; the edge uv receives the label f(u) + f(v). A graph G is A-cordial if there is a vertex-labeling such that (1) the vertex label classes differ in size by at most one and (2) the induced edge label classes differ in size by at most one. The problem of A-cordial labelings of graphs can be naturally extended for hypergraphs. It was shown that not every 2-uniform hypertree (i.e., tree) admits a ℤ2 × ℤ2-cordial labeling [8]. The situation changes if we consider p-uniform hypertrees for a bigger p. We prove that a p-uniform hypertree is ℤ2 × ℤ2-cordial for any p > 2, and so is every path hypergraph in which all edges have size at least 3. The property is not valid universally in the class of hypergraphs of maximum degree 1, for which we provide a necessary and sufficient condition.
Źródło:
Discussiones Mathematicae Graph Theory; 2021, 41, 4; 1021-1040
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decompositions of complete 3-uniform hypergraphs into cycles of constant prime length
Autorzy:
Lakshmi, R
Poovaragavan, T.
Powiązania:
https://bibliotekanauki.pl/articles/255686.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
uniform hypergraph
cycle decomposition
Opis:
A complete 3-unilorm hypergraph of order n has vertex set V with \V\ = n and the set ol all 3-subsets of V as its edge set. A t-cycle in this hypergraph is v1, e1, v2, e2,… , vt, et, v1 where v1, v2,…vt are distinct vertices and e1, e-2,..., et are distinct edges such that [formula] and [formula] A decomposition of a hypergraph is a partition of its edge set into edge-disjoint subsets. In this paper, we give necessary and sufficient conditions for a decomposition of the complete 3-unilorm hypergraph of order n into p-cycles, whenever p is prime.
Źródło:
Opuscula Mathematica; 2020, 40, 4; 509-516
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Niche Hypergraphs of Products of Digraphs
Autorzy:
Sonntag, Martin
Teichert, Hanns-Martin
Powiązania:
https://bibliotekanauki.pl/articles/32083765.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
niche hypergraph
product of digraphs
competition hypergraph
Opis:
If $ D = (V, A) $ is a digraph, its niche hypergraph \( N \mathcal{H} (D) = (V, \mathcal{E} ) \) has the edge set \( \mathcal{E} = \{ e \subseteq V \ | \ |e| \le 2 \land \exists υ \in V : e = N_D^− (υ) \lor e=N_D^+ (υ) \} \). Niche hypergraphs generalize the well-known niche graphs and are closely related to competition hypergraphs as well as common enemy hypergraphs. For several products \( D_1 \circ D_2 \) of digraphs \( D_1 \) and \( D_2 \), we investigate the relations between the niche hypergraphs of the factors \( D_1 \), \( D_2 \) and the niche hypergraph of their product \( D_1 \circ D_2 \).
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 279-295
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the α-Spectral Radius of Uniform Hypergraphs
Autorzy:
Guo, Haiyan
Zhou, Bo
Powiązania:
https://bibliotekanauki.pl/articles/31551887.pdf
Data publikacji:
2020-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
adjacency tensor
uniform hypergraph
extremal hypergraph
α-spectral radius
α-Perron vector
Opis:
For \(0 ≤ \alpha < 1\) and a uniform hypergraph $G$, the \(\alpha\)-spectral radius of $G$ is the largest $H$-eigenvalue of \(\alpha\mathcal{D}(G)+(1−\alpha)\mathcal{A}(G)\), where \(\mathcal{D}(G)\) and \(\mathcal{A}(G)\) are the diagonal tensor of degrees and the adjacency tensor of $G$, respectively. We give upper bounds for the \(\alpha\)-spectral radius of a uniform hypergraph, propose some transformations that increase the \(\alpha\)-spectral radius, and determine the unique hypergraphs with maximum \(\alpha\)-spectral radius in some classes of uniform hypergraphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 2; 559-575
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Subdivision of hypergraphs and their colorings
Autorzy:
Iradmusa, Moharram N.
Powiązania:
https://bibliotekanauki.pl/articles/255017.pdf
Data publikacji:
2020
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
hypergraph
uniform hypergraph
subdivision of hypergraph
Opis:
In this paper we introduce the subdivision of hypergraphs, study their properties and parameters and investigate their weak and strong chromatic numbers in various cases.
Źródło:
Opuscula Mathematica; 2020, 40, 2; 271-290
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decomposing complete 3-uniform hypergraph $K_n^{(3)}$ into 7-cycles
Autorzy:
Meihua, -
Guan, Meiling
Jirimutu, -
Powiązania:
https://bibliotekanauki.pl/articles/1397516.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
uniform hypergraph
7-cycle
cycle decomposition
Opis:
We use the Katona-Kierstead definition of a Hamiltonian cycle in a uniform hypergraph. A decomposition of complete k-uniform hypergraph $K_n^{(k)}$ into Hamiltonian cycles was studied by Bailey-Stevens and Meszka-Rosa. For $ n \equiv 2,4, 5 (mod 6)$, we design an algorithm for decomposing the complete 3-uniform hypergraphs into Hamiltonian cycles by using the method of edge-partition. A decomposition of $ K_n^{(3)}$ into 5-cycles has been presented for all admissible $ n \leq 17$, and for all $n = 4^m + 1$ when $m$ is a positive integer. In general, the existence of a decomposition into 5-cycles remains open. In this paper, we show if $42 | (n — 1)(n — 2)$ and if there exist $\lambda = (n-1)(n-2)/42$ sequences $(k_{i0}, k_{i1},…..,k_{i6})$ on $D_{\text{all}}(n)$, then $K_n^{(3)}$ can be decomposed into 7-cycles. We use the method of edge-partition and cycle sequence. We find a decomposition of $K_{37}^{(3)}$ and $K_{43}^{(3)}$ into 7-cycles.
Źródło:
Opuscula Mathematica; 2019, 39, 3; 383-393
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł

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