The Density of Extreme Points in Complex Polynomial Approximation
نویسندگان
چکیده
Let K be a compact set in the complex plane having connected and regular complement, and let / be any function continuous on K and analytic in the interior of K. For the polynomials pn(¡) of respective degrees at most n of best uniform approximation to / on K, we investigate the density of the sets of extreme points And) :={zeK: \f{z) p*n{f)(z)\ = \\f Pn(¡)\\K} in the boundary of K.
منابع مشابه
On Integral Operator and Argument Estimation of a Novel Subclass of Harmonic Univalent Functions
Abstract. In this paper we define and verify a subclass of harmonic univalent functions involving the argument of complex-value functions of the form f = h + ¯g and investigate some properties of this subclass e.g. necessary and sufficient coefficient bounds, extreme points, distortion bounds and Hadamard product.Abstract. In this paper we define and verify a subclass of harmonic univalent func...
متن کاملBehavior of Polynomials of Best Uniform Approximation
We investigate the asymptotic behavior of the polynomials {Pn(f)}'t' of best uniform approximation to a function f that is continuous on a compact set K of the complex plane C and analytic in the interior of K, where K has connected complement. For example, we show that for "most" functions f, the error f -Pn(f) does not decrease faster at interior points of K than on K itself. We also describe...
متن کاملA method to obtain the best uniform polynomial approximation for the family of rational function
In this article, by using Chebyshev’s polynomials and Chebyshev’s expansion, we obtain the best uniform polynomial approximation out of P2n to a class of rational functions of the form (ax2+c)-1 on any non symmetric interval [d,e]. Using the obtained approximation, we provide the best uniform polynomial approximation to a class of rational functions of the form (ax2+bx+c)-1 for both cases b2-4a...
متن کاملThe best uniform polynomial approximation of two classes of rational functions
In this paper we obtain the explicit form of the best uniform polynomial approximations out of Pn of two classes of rational functions using properties of Chebyshev polynomials. In this way we present some new theorems and lemmas. Some examples will be given to support the results.
متن کاملNON-POLYNOMIAL QUARTIC SPLINE SOLUTION OF BOUNDARY-VALUE PROBLEM
Quartic non-polynomial spline function approximation in off step points is developed, for the solution of fourth-order boundary value problems. Using consistency relation of such spline and suitable choice of parameter,we have obtained second, fourth and sixth orders methods. Convergence analysis of sixth order method has been given. The methods are illustrated by some examples, to verify the or...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2007