Stepanets a I (36 results)

Hardcover. Condition: As New. No Dust Jacket. This monograph can be regarded as a result of the activity of many mathematicians of the 20th century in the field of classical Fourier series and the theory of approximation of periodic functions, beginning with H. Lebesgue, D. Jackson, and S. N. Bernstein. The key point of the monograph is the classification of periodic functions introduced by the author and developed methods that enable one to solve, within the framework of a common approach, traditional problems of approximation theory for large collections of periodic functions, including, as particular cases, the well-known Weyl--Nagy and Sobolev classes as well as classes of functions defined by convolutions with arbitrary summable kernels. The developed methods enable one to solve problems of approximation theory not only in the periodic case but also in the case where objects of approximation are functions locally integrable on the entire axis and functions defined by Cauchy-type integrals in domains of the complex plane bounded by rectifiable Jordan curves. The main results are fairly complete and are presented in the form of either exact or asymptotically exact equalities. Most results of the monograph represent the latest achievements, which have not yet been published in existing monographs. First of all, this refers to problems of regularity and saturation of linear processes of summation and the convergence rate of Fourier series in different metrics, approximation by interpolation polynomials, approximation of locally integrable functions by entire functions of exponential type, and approximation of Cauchy integrals in Jordan domains by Faber polynomials. The monograph also contains entirely new results aimed at the construction of approximation theory in general linear spaces. The present monograph is, in many respects, a store of knowledge accumulated in approximation theory by the beginning of the third millennium and serving for its further development. Due to size, ships within US only. ; tall 8vo 9" - 10" tall; 922 pp. …

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Hardback. Condition: New. 1995 ed. The chapters are split into sections, which, in turn, are split into subsections enumerated by two numbers: the first stands for the number of the section while the second for the number ofthe subsection itself. The same numeration is used for all kinds of statements and formulas. If we refer to statements or formulas in other chapters, we use triple numeration where the first number stands for the chapter and the other two have the same sense. The results presented in this book were discussed on the seminars at the Institute of Mathematics of Ukrainian Academy ofSciences, at the Steklov Mathematical Institute of the Academy of Sciences of the USSR, at Moscow and Tbilisi State Universities. I am deeply grateful to the heads of these seminars Professors V. K. Dzyadyk, N. P. Kor- neichuk, S. B. Stechkin, P. L. U1yanov, and L. V. Zhizhiashvili as well as to the mem- bers ofthese seminars that took an active part in the discussions. In TRODUCTIon It is well known for many years that every 21t -periodic summable function f(x) can be associated in a one-to-one manner with its Fourier series (1. 1) Slfl where I It = - f f(t)cosktdt 1t -It and I It - f f(t)sinktdt.1t -It Therefore, if for approximation of a given function f(*), it is necessary to construct a sequence ofpolynomials Pn (.…

Taschenbuch. Condition: Neu. Druck auf Anfrage Neuware - Printed after ordering - The chapters are split into sections, which, in turn, are split into subsections enumerated by two numbers: the first stands for the number of the section while the second for the number ofthe subsection itself. The same numeration is used for all kinds of statements and formulas. If we refer to statements or formulas in other chapters, we use triple numeration where the first number stands for the chapter and the other two have the same sense. The results presented in this book were discussed on the seminars at the Institute of Mathematics of Ukrainian Academy ofSciences, at the Steklov Mathematical Institute of the Academy of Sciences of the USSR, at Moscow and Tbilisi State Universities. I am deeply grateful to the heads of these seminars Professors V. K. Dzyadyk, N. P. Kor neichuk, S. B. Stechkin, P. L. U1yanov, and L. V. Zhizhiashvili as well as to the mem bers ofthese seminars that took an active part in the discussions. In TRODUCTIon It is well known for many years that every 21t -periodic summable function f(x) can be associated in a one-to-one manner with its Fourier series (1. 1) Slfl where I It = - f f(t)cosktdt 1t -It and I It - f f(t)sinktdt. 1t -It Therefore, if for approximation of a given function f( ), it is necessary to construct a sequence ofpolynomials Pn (.…

Buch. Condition: Neu. Druck auf Anfrage Neuware - Printed after ordering - 1. Classes of Periodic Functions.- 1. Sets of Summable Functions. Moduli of Continuity.- 2. The Classes H [a, b] and H .- 3. Moduli of Continuity in the Spaces Lp. The Classes H p.- 4. Classes of Differentiable Functions.- 5. Conjugate Functions and Their Classes.- 6. Weil-Nagy Classes.- 7. The Classes.- 8. The Classes.- 9. The Classes 35 10. Order Relation for ( , )-Derivatives.- 2. Integral Representations of Deviations of Linear Means Of Fourier Series.- 1. Fourier Sums.- 2. Linear Methods of Summation of Fourier Series. General Aspects.- 3. Integral Representations of n(f;x; ).- 4. Representations of Deviations of Fourier Sums on the Sets and.- 5. Representations of Deviations of Fourier Sums on the Sets and.- 3. Approximations by Fourier Sums in the Spaces c and l1.- 1. Simplest Extremal Problems in the Space C.- 2. Simplest Extremal Problems in the Space L1.- 3. Asymptotic Equalities for n(H ).- 4. Asymptotic Equalities for.- 5. Moduli of Half-Decay of Convex Functions.- 6. Asymptotic Representations for n(f; x) on the Sets.- 7. Asymptotic Equalities for and.- 8. Approximations of Analytic Functions by Fourier Sums in the Uniform Metric.- 9. Approximations of Entire Functions by Fourier Sums in the Uniform Metric.- 10. Asymptotic Equalities for and.- 11. Asymptotic Equalities for and.- 12. Asymptotic Equalities for and.- 13. Approximations of Analytic Functions in the Metric of the Space L.- 14. Asymptotic Equalities for and.- 15. Behavior of a Sequence of Partial Fourier Sums near Their Points of Divergence.- 4. Simultaneous Approximation of Functions and their Derivatives by Fourier Sums.- 1. Statement of the Problem and Auxiliary Facts.- 2. Asymptotic Equalities for.- 3. Asymptotic Equalities for.- 4. Corollaries of Theorems 2.1 and 3.1.- 5.Convergence Rate of the Group of Deviations.- 6. Strong Summability of Fourier Series.- 5. Convergence Rate of Fourier Series and Best Approximations in the Spaces lp.- 1. Approximations in the Space L2.- 2. Jackson Inequalities in the Space L2.- 3. Multiplicators. Marcinkiewicz Theorem. Riesz Theorem. Hardy - Littlewood Theorem.- 4. Imbedding Theorems for the Sets.- 5. Approximations of Functions from the Sets.- 6. Best Approximations of Infinitely Differentiable Functions.- 7. Jackson Inequalities in the Spaces C and Lp.- 6. Best Approximations in the Spaces C and l.- 1. Zeros of Trigonometric Polynomials.- 2. Chebyshev Theorem and de la Vallée Poussin Theorem.- 3. Polynomial of Best Approximation in the Space L.- 4. Approximation of Classes of Convolutions.- 5. Orders of Best Approximations.- 6. Exact Values of Upper Bounds of Best Approximations.- Bibliographical Notes.- References. …

Condition: New. pp. xii + 483.

Condition: New. pp. 380.

Condition: New. pp. xii + 483.

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Condition: New. pp. xii + 483.

Condition: New. pp. xviii + 919.

Condition: New. pp. xviii + 919.

Condition: New. pp. xviii + 919.

Hardback. Condition: New. 1995 ed. The chapters are split into sections, which, in turn, are split into subsections enumerated by two numbers: the first stands for the number of the section while the second for the number ofthe subsection itself. The same numeration is used for all kinds of statements and formulas. If we refer to statements or formulas in other chapters, we use triple numeration where the first number stands for the chapter and the other two have the same sense. The results presented in this book were discussed on the seminars at the Institute of Mathematics of Ukrainian Academy ofSciences, at the Steklov Mathematical Institute of the Academy of Sciences of the USSR, at Moscow and Tbilisi State Universities. I am deeply grateful to the heads of these seminars Professors V. K. Dzyadyk, N. P. Kor- neichuk, S. B. Stechkin, P. L. U1yanov, and L. V. Zhizhiashvili as well as to the mem- bers ofthese seminars that took an active part in the discussions. In TRODUCTIon It is well known for many years that every 21t -periodic summable function f(x) can be associated in a one-to-one manner with its Fourier series (1. 1) Slfl where I It = - f f(t)cosktdt 1t -It and I It - f f(t)sinktdt.1t -It Therefore, if for approximation of a given function f(*), it is necessary to construct a sequence ofpolynomials Pn (.…

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Buch. Condition: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The chapters are split into sections, which, in turn, are split into subsections enumerated by two numbers: the first stands for the number of the section while the second for the number ofthe subsection itself. The same numeration is used for all kinds of statements and formulas. If we refer to statements or formulas in other chapters, we use triple numeration where the first number stands for the chapter and the other two have the same sense. The results presented in this book were discussed on the seminars at the Institute of Mathematics of Ukrainian Academy ofSciences, at the Steklov Mathematical Institute of the Academy of Sciences of the USSR, at Moscow and Tbilisi State Universities. I am deeply grateful to the heads of these seminars Professors V. K. Dzyadyk, N. P. Kor neichuk, S. B. Stechkin, P. L. U1yanov, and L. V. Zhizhiashvili as well as to the mem bers ofthese seminars that took an active part in the discussions. In TRODUCTIon It is well known for many years that every 21t -periodic summable function f(x) can be associated in a one-to-one manner with its Fourier series (1. 1) Slfl where I It = - f f(t)cosktdt 1t -It and I It - f f(t)sinktdt. 1t -It Therefore, if for approximation of a given function f( ), it is necessary to construct a sequence ofpolynomials Pn (. 380 pp. Englisch.…

Taschenbuch. Condition: Neu. This item is printed on demand - it takes 3-4 days longer - Neuware -The chapters are split into sections, which, in turn, are split into subsections enumerated by two numbers: the first stands for the number of the section while the second for the number ofthe subsection itself. The same numeration is used for all kinds of statements and formulas. If we refer to statements or formulas in other chapters, we use triple numeration where the first number stands for the chapter and the other two have the same sense. The results presented in this book were discussed on the seminars at the Institute of Mathematics of Ukrainian Academy ofSciences, at the Steklov Mathematical Institute of the Academy of Sciences of the USSR, at Moscow and Tbilisi State Universities. I am deeply grateful to the heads of these seminars Professors V. K. Dzyadyk, N. P. Kor neichuk, S. B. Stechkin, P. L. U1yanov, and L. V. Zhizhiashvili as well as to the mem bers ofthese seminars that took an active part in the discussions. In TRODUCTIon It is well known for many years that every 21t -periodic summable function f(x) can be associated in a one-to-one manner with its Fourier series (1. 1) Slfl where I It = - f f(t)cosktdt 1t -It and I It - f f(t)sinktdt. 1t -It Therefore, if for approximation of a given function f( ), it is necessary to construct a sequence ofpolynomials Pn (. 380 pp. Englisch.…

Condition: New. Dieser Artikel ist ein Print on Demand Artikel und wird nach Ihrer Bestellung fuer Sie gedruckt. Preface. Introduction. 1. Classes of periodic functions. 2. Integral representations of deviations of linear means of Fourier series. 3. Approximations by Fourier sums in the spaces c and L1. 4. Simultaneous approximation of functions and their derivati.…

Gebunden. Condition: New. Dieser Artikel ist ein Print on Demand Artikel und wird nach Ihrer Bestellung fuer Sie gedruckt. Preface. Introduction. 1. Classes of periodic functions. 2. Integral representations of deviations of linear means of Fourier series. 3. Approximations by Fourier sums in the spaces c and L1. 4. Simultaneous approximation of functions and their derivati.…