Pointwise Remez inequality

نویسندگان

چکیده

Abstract The standard well-known Remez inequality gives an upper estimate of the values polynomials on $$[-1,1]$$ [ - 1 , ] if they are bounded by 1 a subset fixed Lebesgue measure. extremal solution is given rescaled Chebyshev for one interval. Andrievskii asked about maximal value at point, again set size. We show that either (one interval) or Akhiezer (two intervals) and prove Totik–Widom bounds value, thereby providing complete asymptotic to problem.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

A REMEZ - TYPE INEQUALITY 3 Theorem 1

The principal result of this paper is a Remez-type inequality for M untz polynomials: p(x) := n X i=0 a i x i ; or equivalently for Dirichlet sums: P(t) := n X i=0 a i e ? i t ; where (i) 1 i=0 is a sequence of distinct real numbers. The most useful form of this inequality states that for every sequence (i) 1 i=0 satisfying 1 X i=0 i 6 =0 1 j i j < 1 there is a constant c depending only on (i) ...

متن کامل

The Remez Inequality for Linear Combinations of Shifted Gaussians

Let Gn := ( f : f(t) = n X j=1 aje −(t−λj) , aj , λj ∈ R ) . In this paper we prove the following result. Theorem (Remez-Type Inequality for Gn). Let s ∈ (0,∞). There is an absolute constant c1 > 0 such that exp(c1(min{ns, ns2} + s)) ≤ sup f ‖f‖R ≤ exp(240(min{n1/2s, ns2} + s)) , where the supremum is taken for all f ∈ Gn satisfying m ({t ∈ R : |f(t)| ≥ 1}) ≤ s . We also prove the right higher ...

متن کامل

A Pointwise Inequality for the Fourth Order Lane-emden Equation

We prove that the following pointwise inequality holds −∆u ≥ √ 2 (p + 1)− cn |x| a 2 u p+1 2 + 2 n− 4 |∇u|2 u in R where cn := 8 n(n−4) , for positive bounded solutions of the fourth order Hénon equation that is ∆u = |x|u in R where a ≥ 0 and p > 1. Motivated by the Moser iteration argument in the regularity theory, we develop an iteration argument to prove the above pointwise inequality. As fa...

متن کامل

A Note on the Sharpness of the Remez-type Inequality for Homogeneous Polynomials on the Sphere

A NOTE ON THE SHARPNESS OF THE REMEZ-TYPE INEQUALITY FOR HOMOGENEOUS POLYNOMIALS ON THE SPHERE M. YATTSELEV Dedicated to Ed Saff on the occasion of his 60th birthday Abstract. Remez-type inequalities provide upper bounds for the uniform norms of polynomials on given compact sets provided that for every where is a subset of of small measure. In this note we obtain an asymptotically sharp Remez-t...

متن کامل

ذخیره 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: Constructive Approximation

سال: 2021

ISSN: ['0176-4276', '1432-0940']

DOI: https://doi.org/10.1007/s00365-021-09562-1