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VIDEO LIBRARY |
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Pointwise Remez inequality P. M. Yuditskii Institute of Analysis, Johannes Kepler University Linz |
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Abstract: The classical Remez inequality provides an exact estimate for a polynomial on a given interval if it is known that the polynomial is bounded by one on a subset of this interval of the given Lebesgue measure. To be precise, let $$ \Pi_n(E):=\{P_n\in \Pi_n:\ |P_n(x)|\le 1,\ x\in E\}. $$ The Lebesgue measure of $$ M_{n,\delta}=\sup_{E:|E|=2-2\delta}\sup_{P_n\in\Pi_n(E)}\sup_{x\in[-1,1]}|P_n(x)|. $$ According to Remez $M_{n,\delta}=T_n\left(\frac{1+\delta}{1-\delta}\right)$, where Since the mid-90s, based on the previous results of T. Erdélyi, E. B. Saff and himself, at several international conferences Vladimir Andrievskii raised the following problem. Find $$ L_{n,\delta}(x_0)=\sup_{E:|E|=2-2\delta}\sup_{P_n\in\Pi_n(E)}|P_n(x_0)|, \quad x_0\in [-1,1]. $$ Note that $\sup_{x_0\in[-1,1]}L_{n,\delta}(x_0)=M_{n,\delta}$. In the talk we present a solution of Andievskii's problem on the pointwise Remez inequality. Language: English Website: https://us02web.zoom.us/j/8618528524?pwd=MmxGeHRWZHZnS0NLQi9jTTFTTzFrQT09 * Zoom conference ID: 861 852 8524 , password: caopa |