New York Journal of Mathematics
Volume 20 (2014) 831-843

  

Mubariz T. Karaev, Suna Saltan, and Tevfik Kunt

Discrete Duhamel product, restriction of weighted shift operators and related problems

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Published: October 5, 2014
Keywords: Discrete Duhamel product, Weighted shift operator, Borel transform, Banach algebra, Spectral multiplicity
Subject: 47B38, 46B15

Abstract
By applying the discrete Duhamel product method we calculate the spectral multiplicity of the direct sum of some operators. In particular, we prove that μ(T|Xi⊕ A)=1+μ(A) and μ(S⊕ A)=2 for the restriction of the weighted shift operator T|Xi, shift operator S and some appropriate operators A on the Banach spaces.

Acknowledgements

This work is supported by Suleyman Demirel University with Project 3465-YL1-13. This paper was supported by King Saud University, Deanship of Scientific Research, College of Science Research Center.


Author information

Mubariz T. Karaev:
Department of Mathematics, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
mgarayev@ksu.edu.sa

Suna Saltan:
Suleyman Demirel University, Department of Mathematics, 32260, Isparta, Turkey
sunasaltan@sdu.edu.tr

Tevfik Kunt:
Suleyman Demirel University, Department of Mathematics, 32260, Isparta, Turkey
tevfik.kunt@gmail.com