共查询到20条相似文献,搜索用时 31 毫秒
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Norihide Tokushige 《Journal of Combinatorial Theory, Series A》2007,114(4):575-596
Let 1?t?7 be an integer and let F be a k-uniform hypergraph on n vertices. Suppose that |A∩B∩C∩D|?t holds for all A,B,C,D∈F. Then we have if holds for some ε>0 and all n>n0(ε). We apply this result to get EKR type inequalities for “intersecting and union families” and “intersecting Sperner families.” 相似文献
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Norihide Tokushige 《Discrete Mathematics》2010,310(3):453-460
Let m(n,k,r,t) be the maximum size of satisfying |F1∩?∩Fr|≥t for all F1,…,Fr∈F. We prove that for every p∈(0,1) there is some r0 such that, for all r>r0 and all t with 1≤t≤⌊(p1−r−p)/(1−p)⌋−r, there exists n0 so that if n>n0 and p=k/n, then . The upper bound for t is tight for fixed p and r. 相似文献
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Sukumar Das Adhikari 《Journal of Combinatorial Theory, Series A》2008,115(1):178-184
Let G be a finite abelian group of order n and let A⊆Z be non-empty. Generalizing a well-known constant, we define the Davenport constant of G with weight A, denoted by DA(G), to be the least natural number k such that for any sequence (x1,…,xk) with xi∈G, there exists a non-empty subsequence (xj1,…,xjl) and a1,…,al∈A such that . Similarly, for any such set A, EA(G) is defined to be the least t∈N such that for all sequences (x1,…,xt) with xi∈G, there exist indices j1,…,jn∈N,1?j1<?<jn?t, and ?1,…,?n∈A with . In the present paper, we establish a relation between the constants DA(G) and EA(G) under certain conditions. Our definitions are compatible with the previous generalizations for the particular group G=Z/nZ and the relation we establish had been conjectured in that particular case. 相似文献
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Mohammad Javaheri 《Journal of Mathematical Analysis and Applications》2010,361(2):332-337
Let γ:[0,1]→2[0,1] be a continuous curve such that γ(0)=(0,0), γ(1)=(1,1), and γ(t)∈2(0,1) for all t∈(0,1). We prove that, for each n∈N, there exists a sequence of points Ai, 0?i?n+1, on γ such that A0=(0,0), An+1=(1,1), and the sequences and , 0?i?n, are positive and the same up to order, where π1, π2 are projections on the axes. 相似文献
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So-Chin Chen 《Journal of Mathematical Analysis and Applications》2004,297(1):38-47
In contrast to the famous Henkin-Skoda theorem concerning the zero varieties of holomorphic functions in the Nevanlinna class on the open unit ball Bn in , n?2, it is proved in this article that for any nonnegative, increasing, convex function ?(t) defined on , there exists satisfying such that there is no f∈Hp(Bn), 0<p<∞, with . Here Ng(ζ,1) denotes the integrated zero counting function associated with the slice function gζ. This means that the zero sets of holomorphic functions belonging to the Hardy spaces Hp(Bn), 0<p<∞, unlike that of the holomorphic functions in the Nevanlinna class, cannot be characterized in the above manner. 相似文献
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Dhruv Mubayi 《Journal of Combinatorial Theory, Series A》2006,113(3):547-550
Fix integers k?3 and n?3k/2. Let F be a family of k-sets of an n-element set so that whenever A,B,C∈F satisfy |A∪B∪C|?2k, we have A∩B∩C≠∅. We prove that with equality only when ?F∈FF≠∅. This settles a conjecture of Frankl and Füredi [2], who proved the result for n?k2+3k. 相似文献
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A simple proof for a theorem of Luxemburg and Zaanen 总被引:1,自引:0,他引:1
Mohamed Ali Toumi 《Journal of Mathematical Analysis and Applications》2006,322(2):1231-1234
In this paper a simple proof for the following theorem, due to Luxemburg and Zaanen is given: an Archimedean vector lattice A is Dedekind σ-complete if and only if A has the principal projection property and A is uniformly complete. As an application, we give a new and short proof for the following version of Freudenthal's spectral theorem: let A be a uniformly complete vector lattice with the principal projection property and let 0<u∈A. For any element w in A such that 0?w?u there exists a sequence in A which satisfies , where each element sn is of the form , with real numbers α1,…,αk such that 0?αi?1 (i=1,…,k) and mutually disjoint components p1,…,pk of u. 相似文献
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Peter Borg 《Discrete Mathematics》2009,309(14):4750-4753
Families A1,…,Ak of sets are said to be cross-intersecting if for any Ai∈Ai and Aj∈Aj, i≠j. A nice result of Hilton that generalises the Erd?s-Ko-Rado (EKR) Theorem says that if r≤n/2 and A1,…,Ak are cross-intersecting sub-families of , then
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Mihály Pituk 《Linear algebra and its applications》2011,434(2):490-500
Let An,n∈N, be a sequence of k×k matrices which converge to a matrix A as n→∞. It is shown that if xn,n∈N, is a sequence of nonnegative nonzero vectors such that
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Hao Pan 《Journal of Number Theory》2006,117(1):216-221
Let k,m,n?2 be integers. Let A be a subset of {0,1,…,n} with 0∈A and the greatest common divisor of all elements of A is 1. Suppose that
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For all non-negative integers n1,n2,n3,j1,j2 and j3 with nk+jk>1 for k=1,2,3, (nk,jk)≠(nl,jl) if k≠l, j3=n3−1 and jk≠nk−1 for k=1,2, we study the center variety of the 6-parameter family of real planar polynomial vector given, in complex notation, by , where z=x+iy and A,B,C∈C\{0}. 相似文献
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Let (|q|<1). For k∈N it is shown that there exist k rational numbers A(k,0),…,A(k,k−1) such that
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Chris J. Conidis 《Annals of Pure and Applied Logic》2010,162(1):83-88
We prove that if S is an ω-model of weak weak König’s lemma and , is incomputable, then there exists , such that A and B are Turing incomparable. This extends a recent result of Ku?era and Slaman who proved that if S0 is a Scott set (i.e. an ω-model of weak König’s lemma) and A∈S0, A⊆ω, is incomputable, then there exists B∈S0, B⊆ω, such that A and B are Turing incomparable. 相似文献