An extension of the a-numerical radius on $$C^*$$ -algebras

Banach Journal of Mathematical Analysis - Tập 17 - Trang 1-23 - 2023
Mohamed Mabrouk1,2, Ali Zamani3
1Faculty of Sciences of Sfax, Department of Mathematics, University of Sfax, Sfax, Tunisia
2Department of Mathematics, Faculty of Applied Sciences, Umm Al-Qura University, Makkah, Saudi Arabia
3School of Mathematics and Computer Sciences, Damghan University, Damghan, Iran

Tóm tắt

Let a be a positive element in a unital $$C^*$$ -algebra $$\mathfrak {A}$$ . We define a semi-norm on $$\mathfrak {A}$$ , which generalizes the a-operator semi-norm and the a-numerical radius. We investigate the basic properties of this semi-norm and prove inequalities involving it. Further, we derive new upper and lower bounds for the a-numerical radii of elements in $$\mathfrak {A}$$ . Some other related results are also discussed.

Tài liệu tham khảo

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