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Wyszukujesz frazę "Hamiltonicity" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Toughness, Forbidden Subgraphs, and Hamilton-Connected Graphs
Autorzy:
Zheng, Wei
Broersma, Hajo
Wang, Ligong
Powiązania:
https://bibliotekanauki.pl/articles/32361744.pdf
Data publikacji:
2022-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
toughness
forbidden subgraph
Hamilton-connected graph
Hamiltonicity
Opis:
A graph G is called Hamilton-connected if for every pair of distinct vertices {u, v} of G there exists a Hamilton path in G that connects u and v. A graph G is said to be t-tough if t·ω(G − X) ≤ |X| for all X ⊆ V (G) with ω(G − X) > 1. The toughness of G, denoted τ (G), is the maximum value of t such that G is t-tough (taking τ (Kn) = ∞ for all n ≥ 1). It is known that a Hamilton-connected graph G has toughness τ (G) > 1, but that the reverse statement does not hold in general. In this paper, we investigate all possible forbidden subgraphs H such that every H-free graph G with τ (G) > 1 is Hamilton-connected. We find that the results are completely analogous to the Hamiltonian case: every graph H such that any 1-tough H-free graph is Hamiltonian also ensures that every H-free graph with toughness larger than one is Hamilton-connected. And similarly, there is no other forbidden subgraph having this property, except possibly for the graph K1 ∪ P4 itself. We leave this as an open case.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 1; 187-196
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note introducing Cayley graphs and group-coset graphs generated by graph packings
Autorzy:
Rosiek, R.
Woźniak, M.
Powiązania:
https://bibliotekanauki.pl/articles/2050792.pdf
Data publikacji:
2004
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Cayley graphs
hamiltonicity
packing of graphs
Opis:
The aim of this paper is to construct a class of vertex-transitive graphs that includes the Kneser graphs as a special case. The class will be based on the notion of packing of graphs. Certain families of graphs within this class will be examined more closely, and some of their properties, such as hamiltonicity, will be investigated.
Źródło:
Opuscula Mathematica; 2004, 24, 2; 203-221
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
More Aspects of Arbitrarily Partitionable Graphs
Autorzy:
Bensmail, Julien
Li, Binlong
Powiązania:
https://bibliotekanauki.pl/articles/32222538.pdf
Data publikacji:
2022-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
arbitrarily partitionable graphs
partition into connected subgraphs
Hamiltonicity
Opis:
A graph G of order n is arbitrarily partitionable (AP) if, for every sequence (n1, . . ., np) partitioning n, there is a partition (V1, . . ., Vp) of V (G) such that G[Vi] is a connected ni-graph for i = 1, . . ., p. The property of being AP is related to other well-known graph notions, such as perfect matchings and Hamiltonian cycles, with which it shares several properties. This work is dedicated to studying two aspects behind AP graphs. On the one hand, we consider algorithmic aspects of AP graphs, which received some attention in previous works. We first establish the NP-hardness of the problem of partitioning a graph into connected subgraphs following a given sequence, for various new graph classes of interest. We then prove that the problem of deciding whether a graph is AP is in NP for several classes of graphs, confirming a conjecture of Barth and Fournier for these. On the other hand, we consider the weakening to APness of su cient conditions for Hamiltonicity. While previous works have suggested that such conditions can sometimes indeed be weakened, we here point out cases where this is not true. This is done by considering conditions for Hamiltonicity involving squares of graphs, and claw- and net-free graphs.
Źródło:
Discussiones Mathematicae Graph Theory; 2022, 42, 4; 1237-1261
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remarks on partially square graphs, hamiltonicity and circumference
Autorzy:
Kheddouci, Hamamache
Powiązania:
https://bibliotekanauki.pl/articles/743495.pdf
Data publikacji:
2001
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
partially square graph
claw-free graph
independent set
hamiltonicity and circumference
Opis:
Given a graph G, its partially square graph G* is a graph obtained by adding an edge (u,v) for each pair u, v of vertices of G at distance 2 whenever the vertices u and v have a common neighbor x satisfying the condition $N_G(x) ⊆ N_G[u] ∪ N_G[v]$, where $N_G[x] = N_G(x) ∪ {x}$. In the case where G is a claw-free graph, G* is equal to G². We define $σ°ₜ = min{ ∑_{x∈S} d_G(x):S is an independent set in G* and |S| = t}$. We give for hamiltonicity and circumference new sufficient conditions depending on σ° and we improve some known results.
Źródło:
Discussiones Mathematicae Graph Theory; 2001, 21, 2; 255-266
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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