Open Access
Spring 2017 On maps compressing the numerical range between $C^*$-algebras
Aschwag Fahad Albideewi, Mohamed Mabruk
Adv. Oper. Theory 2(2): 108-113 (Spring 2017). DOI: 10.22034/aot.1612-1067


In this paper, we deal with the problem of characterizing linear maps compressing the numerical range. A counterexample is given to show that such a map need not be a Jordan $*$-homomorphism in general even if the $C^*$-algebras are commutative. Next, under an auxiliary condition we show that such a map is a Jordan $*$-homomorphism.


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Aschwag Fahad Albideewi. Mohamed Mabruk. "On maps compressing the numerical range between $C^*$-algebras." Adv. Oper. Theory 2 (2) 108 - 113, Spring 2017.


Received: 2 December 2016; Accepted: 16 February 2017; Published: Spring 2017
First available in Project Euclid: 4 December 2017

zbMATH: 06711471
MathSciNet: MR3730062
Digital Object Identifier: 10.22034/aot.1612-1067

Primary: 15A86 , 47A12
Secondary: 46L05 , 47B49

Keywords: $C^*$-algebra , compressing the numerical range , Jordan $*$-homomorphism , numerical range

Rights: Copyright © 2017 Tusi Mathematical Research Group

Vol.2 • No. 2 • Spring 2017
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