Extremal functions of the Nevanlinna-Pick problem and Douglas algebras
Studia Mathematica, Tome 105 (1993) no. 2, pp. 151-158
Voir la notice de l'article provenant de la source Institute of Mathematics Polish Academy of Sciences
The Nevanlinna-Pick problem at the zeros of a Blaschke product B having a solution of norm smaller than one is studied. All its extremal solutions are invertible in the Douglas algebra D generated by B. If B is a finite product of sparse Blaschke products (Newman Blaschke products, Frostman Blaschke products) then so are all the extremal solutions. For a Blaschke product B a formula is given for the number C(B) such that if the NP-problem has a solution of norm smaller than C(B) then all its extremal solutions are Carleson Blaschke products, i.e. can be represented as finite products of interpolating Blaschke products.
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author = {V. Tolokonnikov},
title = {Extremal functions of the {Nevanlinna-Pick} problem and {Douglas} algebras},
journal = {Studia Mathematica},
pages = {151--158},
publisher = {mathdoc},
volume = {105},
number = {2},
year = {1993},
doi = {10.4064/sm-105-2-151-158},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-105-2-151-158/}
}
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%0 Journal Article %A V. Tolokonnikov %T Extremal functions of the Nevanlinna-Pick problem and Douglas algebras %J Studia Mathematica %D 1993 %P 151-158 %V 105 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm-105-2-151-158/ %R 10.4064/sm-105-2-151-158 %G en %F 10_4064_sm_105_2_151_158
V. Tolokonnikov. Extremal functions of the Nevanlinna-Pick problem and Douglas algebras. Studia Mathematica, Tome 105 (1993) no. 2, pp. 151-158. doi: 10.4064/sm-105-2-151-158
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