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This article is cited in 3 scientific papers (total in 3 papers)
Brief communications
Ideal $F$-norms on $C^*$-algebras. II
A. M. Bikchentaev Kazan Federal University, 18 Kremlyovskaya str., Kazan, 420008 Russia
Abstract:
We study ideal $F$-norms
$\|\cdot\|_p$, $0 < p <+\infty$ associated with a trace
$\varphi$ on a $C^*$-algebra $\mathcal{A}$. If $A, B$ of
$\mathcal{A}$ are such that $|A|\leq |B|$, then
$\|A\|_p \leq \|B\|_p$. We have
$\|A\|_p=\|A^*\|_p$ for all $A$ from $\mathcal{A}$ ($0 <
p <+\infty$) and $\|\cdot\|_p$ is a seminorm for
$1 \leq p <+\infty$. We estimate the distance from any
element of unital $\mathcal{A}$ to the scalar subalgebra
in the seminorm $\|\cdot\|_1$.
We investigate geometric properties of semiorthogonal
projections from
$\mathcal{A}$.
If a trace $\varphi$ is finite, then the set of all
finite sums of pairwise products of projections and
semiorthogonal projections
(in any order) of $\mathcal{A}$ with coefficients from
$\mathbb{R}^+ $
is not dense in $\mathcal{A}$.
Keywords:
Hilbert space, linear operator, projection, semiorthogonal projection, unitary operator, inequality, $C^*$-algebra, trace, ideal $F$-norm.
Received: 10.09.2018 Revised: 17.09.2018 Accepted: 26.09.2018
Citation:
A. M. Bikchentaev, “Ideal $F$-norms on $C^*$-algebras. II”, Izv. Vyssh. Uchebn. Zaved. Mat., 2019, no. 3, 90–96; Russian Math. (Iz. VUZ), 63:3 (2019), 78–82
Linking options:
https://www.mathnet.ru/eng/ivm9449 https://www.mathnet.ru/eng/ivm/y2019/i3/p90
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