scholarly journals Fuzzy Annihilator Ideals of C -Algebra

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wondwosen Zemene Norahun ◽  
Teferi Getachew Alemayehu ◽  
Gezahagne Mulat Addis
Keyword(s):  
Boolean Algebra ◽  
Complete Boolean Algebra ◽  
Sufficient Condition ◽  
C Algebra ◽  
C Algebras

In this paper, we introduce the concept of relative fuzzy annihilator ideals in C-algebras and investigate some its properties. We characterize relative fuzzy annihilators in terms of fuzzy points. It is proved that the class of fuzzy ideals of C-algebras forms Heything algebra. We observe that the class of all fuzzy annihilator ideals can be made as a complete Boolean algebra. Moreover, we study the concept of fuzzy annihilator preserving homomorphism. We provide a sufficient condition for a homomorphism to be a fuzzy annihilator preserving.

ON ANNIHILATOR IDEALS OF C-ALGEBRAS

2013 ◽  
Vol 06 (01) ◽  
pp. 1350009
Author(s):  
M. SAMBASIVA RAO
Keyword(s):  
Boolean Algebra ◽  
Complete Boolean Algebra ◽  
C Algebra ◽  
C Algebras ◽  
Annihilator Ideal ◽  
Equivalent Conditions

The concept of annihilator ideals is introduced in C-algebras. Some properties of these annihilator ideals are studied and then proved that the class of all annihilator ideals forms a complete Boolean algebra. A set of equivalent conditions are obtained for every ideal of a C-algebra to become an annihilator ideal. Some properties of homomorphic images and inverse images of annihilators ideals of a C-algebra are studied.

scholarly journals $S$-regularity and the corona factorization property

2006 ◽  
Vol 99 (2) ◽  
pp. 204 ◽  
Author(s):  
D. Kucerovsky ◽  
P. W. Ng
Keyword(s):  
Fundamental Property ◽  
Sufficient Condition ◽  
Factorization Property ◽  
Stable Property ◽  
C Algebra ◽  
C Algebras ◽  
The Third ◽  
Explicit Reference ◽  
Stable Algebra ◽  
Extension Algebra

Stability is an important and fundamental property of $C^{*}$-algebras. Given a short exact sequence of $C^{*}$-algebras $0\longrightarrow B\longrightarrow E\longrightarrow A\longrightarrow 0$ where the ends are stable, the middle algebra may or may not be stable. We say that the first algebra, $B$, is $S$-regular if every extension of $B$ by a stable algebra $A$ has a stable extension algebra, $E$. Rördam has given a sufficient condition for $S$-regularity. We define a new condition, weaker than Rördam's, which we call the corona factorization property, and we show that the corona factorization property implies $S$-regularity. The corona factorization property originated in a study of the Kasparov $KK^1(A,B)$ group of extensions, however, we obtain our results without explicit reference to $KK$-theory. Our main result is that for a separable stable $C^{*}$-algebra $B$ the first two of the following properties (which we define later) are equivalent, and both imply the third. With additional hypotheses on the $C^{*}$-algebra, all three properties are equivalent. $B$ has the corona factorization property. Stability is a stable property for full hereditary subalgebras of $B$. $B$ is $S$-regular. We also show that extensions of separable stable $C^{*}$-algebras with the corona factorization property give extension algebras with the corona factorization property, extending the results of [9].

Discontinuous homomorphisms from C*-algebras

1991 ◽  
Vol 110 (1) ◽  
pp. 147-150 ◽  
Author(s):  
D. W. B. Somerset
Keyword(s):  
Banach Algebra ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
C Algebra ◽  
C Algebras ◽  
Necessary And Sufficient

AbstractA necessary and sufficient condition is given for a unital C*-algebra A to admit a discontinuous homomorphism into a Banach algebra which is continuous on its centre. The condition is that A must have a Glimm ideal G such that the C*-algebra A/G admits a discontinuous homomorphism into a Banach algebra.

scholarly journals C*-ALGEBRAS THAT ARE ISOMORPHIC AFTER TENSORING AND FULL PROJECTIONS

2004 ◽  
Vol 47 (3) ◽  
pp. 659-668
Author(s):  
Kazunori Kodaka
Keyword(s):  
Matrix Algebra ◽  
Subject Classification ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Primary 46L05 ◽  
C Algebra ◽  
C Algebras ◽  
Necessary And Sufficient

AbstractLet $A$ be a unital $C^*$-algebra and for each $n\in\mathbb{N}$ let $M_n$ be the $n\times n$ matrix algebra over $\mathbb{C}$. In this paper we shall give a necessary and sufficient condition that there is a unital $C^*$-algebra $B$ satisfying $A\not\cong B$ but for which $A\otimes M_n\cong B\otimes M_n$ for some $n\in\mathbb{N}\setminus\{1\}$. Also, we shall give some examples of unital $C^*$-algebras satisfying the above property.AMS 2000 Mathematics subject classification: Primary 46L05

scholarly journals The Centre-Quotient Property and Weak Centrality for C*-Algebras

2020 ◽  
Author(s):  
Robert J Archbold ◽  
Ilja Gogić
Keyword(s):  
Central Element ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
C Algebra ◽  
C Algebras ◽  
Necessary And Sufficient ◽  
Equivalent Conditions ◽  
Quotient Property

Abstract We give a number of equivalent conditions (including weak centrality) for a general $C^*$-algebra to have the centre-quotient property. We show that every $C^*$-algebra $A$ has a largest weakly central ideal $J_{wc}(A)$. For an ideal $I$ of a unital $C^*$-algebra $A$, we find a necessary and sufficient condition for a central element of $A/I$ to lift to a central element of $A$. This leads to a characterisation of the set $V_A$ of elements of an arbitrary $C^*$-algebra $A$, which prevent $A$ from having the centre-quotient property. The complement $\textrm{CQ}(A):= A \setminus V_A$ always contains $Z(A)+J_{wc}(A)$ (where $Z(A)$ is the centre of $A$), with equality if and only if $A/J_{wc}(A)$ is abelian. Otherwise, $\textrm{CQ}(A)$ fails spectacularly to be a $C^*$-subalgebra of $A$.

scholarly journals Closable derivations of simple C*-algebras

1983 ◽  
Vol 24 (2) ◽  
pp. 181-183 ◽  
Author(s):  
Assadollah Niknam
Keyword(s):  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
C Algebra ◽  
C Algebras ◽  
Necessary And Sufficient

In this note we show that any derivation of a simple C*-algebra, whose range is not dense, is closable. We also derive a necessary and sufficient condition for a *-derivation of a C*-algebra, which is defined on the domain of a closed *- derivation, to be closed.

scholarly journals Inclusions of unital $C^*$-algebras of index-finite type with depth 2 induced by saturated actions of finite dimensional $C^*$-Hopf algebras

2009 ◽  
Vol 104 (2) ◽  
pp. 221
Author(s):  
Kazunori Kodaka ◽  
Yamotsu Teruya
Keyword(s):  
Hopf Algebra ◽  
Conditional Expectation ◽  
Hopf Algebras ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
C Algebra ◽  
C Algebras ◽  
Finite Dimensional ◽  
Sigma H ◽  
Necessary And Sufficient

Let $B$ be a unital $C^*$-algebra and $H$ a finite dimensional $C^*$-Hopf algebra with its dual $C^*$-Hopf algebra $H^0$. We suppose that there is a saturated action of $H$ on $B$ and we denote by $A$ its fixed point $C^*$-subalgebra of $B$. Let $E$ be the canonical conditional expectation from $B$ onto $A$. In the present paper, we shall give a necessary and sufficient condition that there are a weak action of $H^0$ on $A$ and a unitary cocycle $\sigma$ of $H^0 \otimes H^0 $ to $A$ satisfying that there is an isomorphism $\pi$ of $A\rtimes_{\sigma}H^0 $ onto $B$, which is the twisted crossed product of $A$ by the weak action of $H^0$ on $A$ and the unitary cocycle $\sigma$, such that $F=E\circ \pi$, where $F$ is the canonical conditional expectation from $A\rtimes_{\sigma}H^0 $ onto $A$.

scholarly journals Nuclear subalgebras of UHF C*-algebras

1986 ◽  
Vol 29 (1) ◽  
pp. 97-100 ◽  
Author(s):  
R. J. Archbold ◽  
Alexander Kumjian
Keyword(s):  
Tensor Product ◽  
Inductive Limit ◽  
Inductive Limits ◽  
C Algebra ◽  
C Algebras ◽  
Finite Dimensional ◽  
The Family ◽  
Algebraic Tensor Product

A C*-algebra A is said to be approximately finite dimensional (AF) if it is the inductive limit of a sequence of finite dimensional C*-algebras(see [2], [5]). It is said to be nuclear if, for each C*-algebra B, there is a unique C*-norm on the *-algebraic tensor product A ⊗B [11]. Since finite dimensional C*-algebras are nuclear, and inductive limits of nuclear C*-algebras are nuclear [16];,every AF C*-algebra is nuclear. The family of nuclear C*-algebras is a large and well-behaved class (see [12]). The AF C*-algebras for a particularly tractable sub-class which has been completely classified in terms of the invariant K0 [7], [5].

On C*-Algebras Associated with Subshifts

1997 ◽  
Vol 08 (03) ◽  
pp. 357-374 ◽  
Author(s):  
Kengo Matsumoto
Keyword(s):  
Symbolic Dynamics ◽  
Markov Shift ◽  
C Algebra ◽  
C Algebras ◽  
Markov Shifts ◽  
Universal Properties

We construct and study C*-algebras associated with subshifts in symbolic dynamics as a generalization of Cuntz–Krieger algebras for topological Markov shifts. We prove some universal properties for the C*-algebras and give a criterion for them to be simple and purely infinite. We also present an example of a C*-algebra coming from a subshift which is not conjugate to a Markov shift.

scholarly journals CUNTZ–PIMSNER C*-ALGEBRAS ASSOCIATED WITH SUBSHIFTS

2008 ◽  
Vol 19 (01) ◽  
pp. 47-70 ◽  
Author(s):  
TOKE MEIER CARLSEN
Keyword(s):  
Partial Isometries ◽  
C Algebra ◽  
C Algebras ◽  
Shift Space

By using C*-correspondences and Cuntz–Pimsner algebras, we associate to every subshift (also called a shift space) 𝖷 a C*-algebra [Formula: see text], which is a generalization of the Cuntz–Krieger algebras. We show that [Formula: see text] is the universal C*-algebra generated by partial isometries satisfying relations given by 𝖷. We also show that [Formula: see text] is a one-sided conjugacy invariant of 𝖷.

Sign in / Sign up

Export Citation Format

Share Document