ON THE CONVERGENCE OF SEQUENCES OF KANTOROVICH OPERATORS IN LEBESGUE SPACES

According to the Weierstrass Approximation Theorem, any continuous function on the closed and bounded interval can be approximated by polynomials. A constructive proof of this theorem uses the so-called Bernstein polynomials. For the approximation of integrable functions, we may consider Kantorov...

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Bibliographic Details
Main Author: Ventura Obie Welly, Maximillian
Format: Final Project
Language:Indonesia
Online Access:https://digilib.itb.ac.id/gdl/view/71845
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Institution: Institut Teknologi Bandung
Language: Indonesia
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Summary:According to the Weierstrass Approximation Theorem, any continuous function on the closed and bounded interval can be approximated by polynomials. A constructive proof of this theorem uses the so-called Bernstein polynomials. For the approximation of integrable functions, we may consider Kantorovich operators as certain modifications for Bernstein polynomials. In this final project, we investigate the behaviour of Kantorovich operators in Lebesgue spaces. We first give a rather ad hoc proof of the uniform boundedness of Kantorovich operators. We then provide two alternative proofs by using the Riesz-Thorin Interpolation Theorem and the boundedness of Hardy-Littlewood maximal operator respectively. In addition, we discuss the convergence of the sequence of Kantorovich operators in Lebesgue spaces of finite exponents. We provide a counterexample to the convergence of Kantorovich operators in the space of essentially bounded functions. We also consider the rate of convergence of Kantorovich operators in a certain subspace of Lebesgue spaces.