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The triangle equality in Hilbert $A$-modules
A. V. Kalinichenkoa, M. A. Plievb a North-Caucasian Institute of Mining and Metallurgy (State Technological University), 44 Nikolaeva str., Vladikavkaz, 362021 Russia
b Southern Mathematical Institute of the Russian Academy of Sciences, 22 Markusa str., Vladikavkaz, 362027 Russia
Abstract:
We show that for any two elements
$x$, $y$ of Hilbert $A$-module $M$ over local $C^*$-algebra $A$ the
generalized triangle equality $|x+y|=|x|+|y|$ holds if and only if
$\langle x,y\rangle=|x||y|$.
Keywords:
local $C^{\ast}$-algebra, Hilbert $A$-module, local Hilbert space, module compact operator, $\ast$-homomorphism, triangle equality.
Received: 29.08.2018 Revised: 29.08.2018 Accepted: 19.12.2018
Citation:
A. V. Kalinichenko, M. A. Pliev, “The triangle equality in Hilbert $A$-modules”, Izv. Vyssh. Uchebn. Zaved. Mat., 2019, no. 10, 38–45; Russian Math. (Iz. VUZ), 63:10 (2019), 33–39
Linking options:
https://www.mathnet.ru/eng/ivm9505 https://www.mathnet.ru/eng/ivm/y2019/i10/p38
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Abstract page: | 224 | Full-text PDF : | 125 | References: | 56 | First page: | 2 |
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