Markov-Bernstein-type inequalities for classes of polynomials with restricted zeros
Author(s) -
Peter Borwein,
Tam�s Erd�lyi
Publication year - 1994
Publication title -
constructive approximation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.921
H-Index - 51
eISSN - 1432-0940
pISSN - 0176-4276
DOI - 10.1007/bf01212567
Subject(s) - mathematics , multiplicative function , polynomial , unit disk , combinatorics , type (biology) , degree (music) , generalization , markov chain , bernstein polynomial , unit (ring theory) , bernstein inequalities , algebraic number , discrete mathematics , mathematical analysis , inequality , ecology , statistics , physics , mathematics education , acoustics , biology
We prove that an absolute constantc>0 exists such that$$|p'(y)| \leqslant c\min \left\{ {n(k + 1),\left( {\frac{{n(k + 1)}}{{1 - y^2 }}} \right)^{1/2} } \right\}\mathop {\max }\limits_{ - 1 \leqslant x \leqslant 1} |p(x)|, - 1 \leqslant y \leqslant 1,$$ for every real algebraic polynomial of degree at mostn having at mostk zeros in the open unit disk {z?C:|z|c, it is a sharp generalization of both Markov's and Bernstein's inequalities.
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