We consider the problems of the best one-sided approximation (from below and from above) in the space of functions integrable on (-1,1) with a weight to the characteristic function of an interval (a,b) from (-1,1) by the set of algebraic polynomials of degree not exceeding a given number. We solve the problems in the case when a and b are nodes of a positive quadrature formula under some conditions on its degree of precision as well as in the case of a symmetric interval for an even weight.
Наилучшее одностороннее интегральное приближение характеристической функции промежутка алгебраическими многочленами: магистерская диссертация
Торгашова, А. Ю. (Author). 2019
Student thesis: Master's Thesis