Hypergraph Ramsey numbers: Triangles versus cliques
نویسندگان
چکیده
A celebrated result in Ramsey Theory states that the order of magnitude of the trianglecomplete graph Ramsey numbers R(3, t) is t/ log t. In this paper, we consider an analogue of this problem for uniform hypergraphs. A triangle is a hypergraph consisting of edges e, f, g such that |e∩ f | = |f ∩ g| = |g ∩ e| = 1 and e ∩ f ∩ g = ∅. For all r ≥ 2, let R(C3,K t ) be the smallest positive integer n such that in every red-blue coloring of the edges of the complete r-uniform hypergraph K n, there exists a red triangle or a blue K r t . We show that there exist constants a, br > 0 such that for all t ≥ 3, at 3 2 (log t) 3 4 ≤ R(C3,K t ) ≤ b3t 3 2
منابع مشابه
The Ramsey Number of Loose Triangles and Quadrangles in Hypergraphs
Asymptotic values of hypergraph Ramsey numbers for loose cycles (and paths) were determined recently. Here we determine some of them exactly, for example the 2-color hypergraph Ramsey number of a k-uniform loose 3-cycle or 4-cycle: R(Ck 3 , Ck 3 ) = 3k − 2 and R(Ck 4 , Ck 4 ) = 4k − 3 (for k > 3). For more than 3 colors we could prove only that R(C3 3 , C3 3 , C3 3) = 8. Nevertheless, the r-col...
متن کاملMulticolor Ramsey numbers for triple systems
Given an r-uniform hypergraph H, the multicolor Ramsey number rk(H) is the minimum n such that every k-coloring of the edges of the complete r-uniform hypergraph K n yields a monochromatic copy of H. We investigate rk(H) when k grows and H is fixed. For nontrivial 3-uniform hypergraphs H, the function rk(H) ranges from √ 6k(1 + o(1)) to double exponential in k. We observe that rk(H) is polynomi...
متن کاملHypergraph Ramsey numbers: tight cycles versus cliques
For s ≥ 4, the 3-uniform tight cycle C s has vertex set corresponding to s distinct points on a circle and edge set given by the s cyclic intervals of three consecutive points. For fixed s ≥ 4 and s 6≡ 0 (mod 3) we prove that there are positive constants a and b with 2 < r(C s ,K 3 t ) < 2 bt log . The lower bound is obtained via a probabilistic construction. The upper bound for s > 5 is proved...
متن کاملThe Ramsey numbers of large trees versus wheels
For two given graphs G1 and G2, the Ramseynumber R(G1,G2) is the smallest integer n such that for anygraph G of order n, either $G$ contains G1 or the complementof G contains G2. Let Tn denote a tree of order n andWm a wheel of order m+1. To the best of our knowledge, only R(Tn,Wm) with small wheels are known.In this paper, we show that R(Tn,Wm)=3n-2 for odd m with n>756m^{10}.
متن کاملImproved Bounds for the Ramsey Number of Tight Cycles Versus Cliques
The 3-uniform tight cycle C s has vertex set Zs and edge set {{i, i+ 1, i+ 2} : i ∈ Zs}. We prove that for every s 6≡ 0 (mod 3) and s ≥ 16 or s ∈ {8, 11, 14} there is a cs > 0 such that the 3-uniform hypergraph Ramsey number r(C s ,K n ) satisfies r(C s ,K n ) < 2cn . This answers in strong form a question of the author and Rödl who asked for an upper bound of the form 2n 1+ǫs for each fixed s ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- J. Comb. Theory, Ser. A
دوره 120 شماره
صفحات -
تاریخ انتشار 2013