Self-complementary hypergraphs

A. Paweł Wojda

Displaying similar documents to “Self-complementary hypergraphs”

A note on k-uniform self-complementary hypergraphs of given order

Artur Szymański, A. Paweł Wojda (2009)

Discussiones Mathematicae Graph Theory

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We prove that a k-uniform self-complementary hypergraph of order n exists, if and only if $(\binom{n}{k})$ is even.

Asymptotic Sharpness of Bounds on Hypertrees

Yi Lin, Liying Kang, Erfang Shan (2017)

Discussiones Mathematicae Graph Theory

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The hypertree can be defined in many different ways. Katona and Szabó introduced a new, natural definition of hypertrees in uniform hypergraphs and investigated bounds on the number of edges of the hypertrees. They showed that a k-uniform hypertree on n vertices has at most [...] (nk−1) $(n k - 1)$ edges and they conjectured that the upper bound is asymptotically sharp. Recently, Szabó verified that the conjecture holds by recursively constructing an infinite sequence of k-uniform hypertrees and...

Variations of uniform completeness related to realcompactness

Miroslav Hušek (2017)

Commentationes Mathematicae Universitatis Carolinae

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Various characterizations of realcompactness are transferred to uniform spaces giving non-equivalent concepts. Their properties, relations and characterizations are described in this paper. A Shirota-like characterization of certain uniform realcompactness proved by Garrido and Meroño for metrizable spaces is generalized to uniform spaces. The paper may be considered as a unifying survey of known results with some new results added.

The generalized Day norm. Part I. Properties

Monika Budzyńska, Aleksandra Grzesik, Mariola Kot (2017)

Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica

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In this paper we introduce a modification of the Day norm in $c_{0} (Γ)$ and investigate properties of this norm.

Almost Self-Complementary 3-Uniform Hypergraphs

Lata N. Kamble, Charusheela M. Deshpande, Bhagyashree Y. Bam (2017)

Discussiones Mathematicae Graph Theory

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It is known that self-complementary 3-uniform hypergraphs on n vertices exist if and only if n is congruent to 0, 1 or 2 modulo 4. In this paper we define an almost self-complementary 3-uniform hypergraph on n vertices and prove that it exists if and only if n is congruent to 3 modulo 4. The structure of corresponding complementing permutation is also analyzed. Further, we prove that there does not exist a regular almost self-complementary 3-uniform hypergraph on n vertices where n is...

On uniform Dini derivatives

N. C. Manna (1970)

Colloquium Mathematicae

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On some global and local geometric properties of Calderón-Lozanovskiĭ spaces

Agata Narloch (2005)

Banach Center Publications

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Criteria for full k-rotundity (k ∈ ℕ, k ≥ 2) and uniform rotundity in every direction of Calderón-Lozanovskiĭ spaces are formulated. A characterization of $H_{μ}$ -points in these spaces is also given.

Noncommutative uniform algebras

Mati Abel, Krzysztof Jarosz (2004)

Studia Mathematica

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We show that a real Banach algebra A such that ||a²|| = ||a||² for a ∈ A is a subalgebra of the algebra $C_{ℍ} (X)$ of continuous quaternion-valued functions on a compact set X.

Generalizations to monotonicity for uniform convergence of double sine integrals over ℝ̅²₊

Péter Kórus, Ferenc Móricz (2010)

Studia Mathematica

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We investigate the convergence behavior of the family of double sine integrals of the form $\int_{0}^{\infty} \int_{0}^{\infty} f (x, y) s i n u x s i n v y d x d y$ , where (u,v) ∈ ℝ²₊:= ℝ₊ × ℝ₊, ℝ₊:= (0,∞), and f: ℝ²₊ → ℂ is a locally absolutely continuous function satisfying certain generalized monotonicity conditions. We give sufficient conditions for the uniform convergence of the remainder integrals $\int_{a ₁}^{b ₁} \int_{a ₂}^{b ₂}$ to zero in (u,v) ∈ ℝ²₊ as maxa₁,a₂ → ∞ and $b_{j} > a_{j} \geq 0$ , j = 1,2 (called uniform convergence in the regular sense). This implies the uniform convergence of the partial...

The sum number of d-partite complete hypergraphs

Hanns-Martin Teichert (1999)

Discussiones Mathematicae Graph Theory

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A d-uniform hypergraph is a sum hypergraph iff there is a finite S ⊆ IN⁺ such that is isomorphic to the hypergraph $⁺_{d} (S) = (V,)$ , where V = S and $= v ₁, . . ., v_{d} : (i \neq j \Rightarrow v_{i} \neq v_{j}) \land \sum_{i = 1}^{d} v_{i} \in S$ . For an arbitrary d-uniform hypergraph the sum number σ = σ() is defined to be the minimum number of isolated vertices $w ₁, . . ., w_{σ} \notin V$ such that $\cup w ₁, . . ., w_{σ}$ is a sum hypergraph. In this paper, we prove $σ (_{n ₁, . . ., n_{d}}^{d}) = 1 + \sum_{i = 1}^{d} (n_{i} - 1) + m i n 0, ⌈ 1 / 2 (\sum_{i = 1}^{d - 1} (n_{i} - 1) - n_{d}) ⌉$ , where $_{n ₁, . . ., n_{d}}^{d}$ denotes the d-partite complete hypergraph; this generalizes the corresponding result of Hartsfield and Smyth [8] for complete bipartite graphs.

A uniform dichotomy for generic $SL (2, ℝ)$ cocycles over a minimal base

Artur Avila, Jairo Bochi (2007)

Bulletin de la Société Mathématique de France

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We consider continuous $SL (2, ℝ)$ -cocycles over a minimal homeomorphism of a compact set $K$ of finite dimension. We show that the generic cocycle either is uniformly hyperbolic or has uniform subexponential growth.

Uniform boundedness of a family of exhaustive set functions

E. Pap (1976)

Matematički Vesnik

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Sum labellings of cycle hypergraphs

Hanns-Martin Teichert (2000)

Discussiones Mathematicae Graph Theory

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A hypergraph is a sum hypergraph iff there are a finite S ⊆ IN⁺ and d̲, [d̅] ∈ IN⁺ with 1 < d̲ ≤ [d̅] such that is isomorphic to the hypergraph $_{d ̲, [d ̅]} (S) = (V,)$ where V = S and $= e \subseteq S : d ̲ \leq | e | \leq [d ̅] \land \sum_{v \in e} v \in S$ . For an arbitrary hypergraph the sum number σ = σ() is defined to be the minimum number of isolated vertices $y ₁, . . ., y_{σ} \notin V$ such that $\cup y ₁, . . ., y_{σ}$ is a sum hypergraph. Generalizing the graph Cₙ we obtain d-uniform hypergraphs where any d consecutive vertices of Cₙ form an edge. We determine sum numbers and investigate properties of sum labellings...

A note on perfect matchings in uniform hypergraphs with large minimum collective degree

Vojtěch Rödl, Andrzej Ruciński, Mathias Schacht, Endre Szemerédi (2008)

Commentationes Mathematicae Universitatis Carolinae

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For an integer $k \geq 2$ and a $k$ -uniform hypergraph $H$ , let $δ_{k - 1} (H)$ be the largest integer $d$ such that every $(k - 1)$ -element set of vertices of $H$ belongs to at least $d$ edges of $H$ . Further, let $t (k, n)$ be the smallest integer $t$ such that every $k$ -uniform hypergraph on $n$ vertices and with $δ_{k - 1} (H) \geq t$ contains a perfect matching. The parameter $t (k, n)$ has been completely determined for all $k$ and large $n$ divisible by $k$ by Rödl, Ruci’nski, and Szemerédi in [, submitted]. The values of $t (k, n)$ are very close to $n / 2 - k$ . In fact, the function $t (k, n) = n / 2 - k + c_{n, k}$ ,...

Some remarks on universality properties of $ℓ_{\infty} / c ₀$

Mikołaj Krupski, Witold Marciszewski (2012)

Colloquium Mathematicae

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We prove that if is not a Kunen cardinal, then there is a uniform Eberlein compact space K such that the Banach space C(K) does not embed isometrically into $ℓ_{\infty} / c ₀$ . We prove a similar result for isomorphic embeddings. Our arguments are minor modifications of the proofs of analogous results for Corson compacta obtained by S. Todorčević. We also construct a consistent example of a uniform Eberlein compactum whose space of continuous functions embeds isomorphically into $ℓ_{\infty} / c ₀$ , but fails to embed...