Lower bound in the Roth theorem for amenable groups
نویسندگان
چکیده
منابع مشابه
A Lower Bound Theorem
Motivated by Candes and Donoho′s work (Candés, E J, Donoho, D L, Recovering edges in ill-posed inverse problems: optimality of curvelet frames. Ann. Stat. 30, 784-842 (2002)), this paper is devoted to giving a lower bound of minimax mean square errors for Riesz fractional integration transforms and Bessel transforms.
متن کاملThe Thue–Siegel–Roth Theorem
In this paper we will give a proof of the Thue-Siegel-Roth Theorem, which states that for any algebraic number α and any ǫ > 0 there exists only a finite number of pairs of coprime integers p, q such that ∣ α − p q ∣ ∣ < 1 q2+ǫ . We will follow the proof as it is presented Leveque’s book, [8, ch 4]. This proof also deals with the more general case when p q is allowed to be an algebraic number i...
متن کاملAn Improved Lower Bound for Folkman’s Theorem
Folkman’s theorem asserts that for each k ∈ N, there exists a natural number n = F (k) such that whenever the elements of [n] are two-coloured, there exists a set A ⊂ [n] of size k with the property that all the sums of the form ∑ x∈B x, where B is a nonempty subset of A, are contained in [n] and have the same colour. In 1989, Erdős and Spencer showed that F (k) ≥ 2ck2/ log , where c > 0 is an ...
متن کاملLower bound theorem for normal pseudomanifolds
In this paper we present a self-contained combinatorial proof of the lower bound theorem for normal pseudomanifolds, including a treatment of the cases of equality in this theorem. We also discuss McMullen and Walkup’s generalised lower bound conjecture for triangulated spheres in the context of the lower bound theorem. Finally, we pose a new lower bound conjecture for non-simply connected tria...
متن کاملAmenable Groups
Throughout we let Γ be a discrete group. For f : Γ → C and each s ∈ Γ we define the left translation action by (s.f)(t) = f(s−1t). Definition 1.1. A group Γ is amenable is there exists a state μ on l∞(Γ) which is invariant under the left translation action: for all s ∈ Γ and f ∈ l∞(Γ), μ(s.f) = μ(f). Example 1.2. Finite groups are amenable: take the state which sends χ{s} to 1 |Γ| for each 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
ژورنال
عنوان ژورنال: Ergodic Theory and Dynamical Systems
سال: 2014
ISSN: 0143-3857,1469-4417
DOI: 10.1017/etds.2014.13