A new type of numerical radius of operators on Hilbert \(C^*\)-module

  • Marzieh Mehrazin
  • Maryam Amyari
  • Mohsen Erfanian OmidvarEmail author


In this paper, we define a new concept of numerical range \(W_{o}(\cdot )\) and prove its basic results. We also define the numerical radius \(\omega _{o}(\cdot )\) and prove that
$$\begin{aligned} \omega _{o}(T)\le |||T|||\le 2\omega _{o}(T). \end{aligned}$$


Hilbert \(\mathscr {A}\) -module Numerical range Numerical radius 

Mathematics Subject Classification

Primary 46L08 47A12 


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Copyright information

© Springer-Verlag Italia S.r.l., part of Springer Nature 2018

Authors and Affiliations

  • Marzieh Mehrazin
    • 1
  • Maryam Amyari
    • 1
  • Mohsen Erfanian Omidvar
    • 1
    Email author
  1. 1.Department of MathematicsMashhad Branch, Islamic Azad UniversityMashhadIran

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