Abstract
In this paper, we investigate key assumptions on some Banach algebras to have quasi-weak normal structure (resp. \(\hbox {quasi-weak}^{\star }\) normal structure) and to prove in particular that fixed point property for Kannan mappings is satisfied on weakly compact convex subsets in this setting. We establish some conditions on a locally compact group G for which the Fourier and Fourier–Stieltjes–Banach algebras A(G) and B(G) have quasi-normal structure. In addition, we give some examples of Banach spaces X such that \({{\mathcal {L}}} (X)\) (the Banach algebra of bounded linear operators on X) and some of its closed two-sided ideals associated with Fredholm perturbations have fixed point properties. Finally, we give some comments and interesting questions related to this area.
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Acknowledgements
I would like to thank the distinguished professor Anthony To-Ming Lau for his invitation at the University of Alberta during the period May 11–May 24, 2019, I express my great respect and admiration to him and to this institution. I am indebted to Canadian government for its noble initiative to facilitate the mobility of foreign researchers and encouraging them to share knowledge with their counterparts in Canada. Also, I am grateful to the anonymous referees for their valuable remarks and suggestions to improve the manuscript.
Funding
This work is supported by the research team RPC (Controllability and Perturbation Results) in the laboratory of Informatics and Mathematics (LIM) at the university of Souk-Ahras (Algeria).
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Dehici, A. Normal structure and fixed point properties for some Banach algebras. J. Fixed Point Theory Appl. 22, 7 (2020). https://doi.org/10.1007/s11784-019-0743-6
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DOI: https://doi.org/10.1007/s11784-019-0743-6
Keywords
- Banach space
- weakly compact convex subset
- \(\hbox {weakly}^{\star }\) compact convex subset
- weak normal structure
- \(\hbox {quasi-weak}^{\star }\) normal structure
- fixed point property
- locally compact group
- Fourier algebra
- Fourier–Stieltjes algebra
- Banach algebra
- von Neumann algebra
- \(\hbox {C}^{\star }\)-algebra
- Radon–Nikodym property
- Dunford–Pettis property
- Schur’s property
- unconditional basis
- hereditarily indecomposable Banach space