Bull. Korean Math. Soc. 2016; 53(6): 1823-1830
Online first article October 7, 2016 Printed November 30, 2016
https://doi.org/10.4134/BKMS.b151005
Copyright © The Korean Mathematical Society.
Takahiko Nakazi
Hokkaido University
Let $H$ and $K$ be two Hilbert spaces, and let $A$ and $B$ be two bounded linear operators from $H$ to $K$. We are interested in Range$B^\ast \supseteq$ Range$A^\ast $. It is well known that this is equivalent to the inequality $A^\ast A\geq\varepsilon B^\ast B$ for a positive constant $\varepsilon$. We study conditions in terms of symbols when $A$ and $B$ are singular integral operators, Hankel operators or Toeplitz operators, etc.
Keywords: singular integral operator, Hankel operator, Toeplitz operator, range inclusion
MSC numbers: Primary 47B35
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