Publication Details:
Journal or Publication Title:
Armenian Journal of Mathematics=Հայկական մաթեմատիկական հանդես
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Title:
On Biorthogonalization of a Dirichlet System Over a Finite Interval
Creator:
Mher Martirosyan ; Davit Martirosyan
Contributor(s):
Գլխ. խմբ.՝ Անրի Ներսեսյան ; Պատ. խմբ.՝ Լինդա Խաչատրյան ; Խմբ. տեղակալ՝ Ռաֆայել Բարխուդարյան
Subject:
Functions of a complex variable ; Approximations and expansions ; Fourier analysis
Coverage:
Abstract:
Ultimately aiming to estimate Dirichlet polynomials, a representation problem for special biorthogonal systems of exponentials is explored in $L^2(0,a)$. If $a=+\infty$, a method of construction of such systems through suitable Blaschke products is known, but the method ceases to operate when $a$ is finite. It turns out that the Blaschke product cannot be even adjusted to maintain the old method for the new situation. The biorthogonal system is then represented by a single determinant of a modified Gram matrix of the original system. Bernstein-type inequalities for Dirichlet polynomials and their higher order derivatives are established. The best constants and extremal polynomials are obtained in terms of the Gram matrix.
Publisher:
National Academy of Sciences of Armenia
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General note:
Electronic Open Access Publication of the National Academy of Sciences of Armenia
Digitization:
ՀՀ ԳԱԱ Հիմնարար գիտական գրադարան