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ЖУРНАЛЫ // Проблемы анализа — Issues of Analysis // Архив

Пробл. анал. Issues Anal., 2021, том 10(28), выпуск 3, страницы 71–90 (Mi pa332)

Эта публикация цитируется в 2 статьях

Smirnov's inequality for polynomials having zeros outside the unit disc

E. G. Kompaneets, V. V. Starkov

Petrozavodsk State University, 33 Lenina pr., Petrozavodsk 185910, Russia

Аннотация: In 1887, the famous chemist D. I. Mendeleev posed the following problem: to estimate $|f'(x)|$ for a real polynomial $f(x)$, satisfying the condition $|f(x)|\leq M$ on $[a, b]$. This question arose when Mendeleev was studying aqueous solutions. The problem was solved by the famous mathematician A. A. Markov, and over the following 100 years was repeatedly modified and extended. For complex polynomials, important inequalities were obtained by S. N. Bernstein and V. I. Smirnov. Many other well-known mathematicians, such as Ch. Pommerenke, G. Szegö, Q. I. Rahman, G. Schmeisser, worked in this subject. Almost all results in this direction significantly use the following condition: all zeros of a majorizing polynomial belong to the closed unit disc. In this paper, we remove this condition. Here a majorizing polynomial may have zeros outside the unit disc. This allows to extend the inequalities of Bernstein and Smirnov.

Ключевые слова: polynomial, the Smirnov inequality, the Bernstein inequality.

УДК: 517.53

MSC: 30C10, 30A10

Поступила в редакцию: 11.09.2021
Исправленный вариант: 28.09.2021
Принята в печать: 23.10.2021

Язык публикации: английский

DOI: 10.15393/j3.art.2021.10970



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