If $A$ is a abelian $C^*$-algebra and $a,b$ are elements in $A$ such that $0\leq a\leq 1,0\leq b\leq 1$ then $0\leq ab\leq 1$.
My problem is:" Is it true if $A$ is not abelian?"
2026-04-04 03:50:56.1775274656
positive elements of $C^*$-algebra
92 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail At
1
There are 1 best solutions below
Related Questions in FUNCTIONAL-ANALYSIS
- On sufficient condition for pre-compactness "in measure"(i.e. in Young measure space)
- Why is necessary ask $F$ to be infinite in order to obtain: $ f(v)=0$ for all $ f\in V^* \implies v=0 $
- Prove or disprove the following inequality
- Unbounded linear operator, projection from graph not open
- $\| (I-T)^{-1}|_{\ker(I-T)^\perp} \| \geq 1$ for all compact operator $T$ in an infinite dimensional Hilbert space
- Elementary question on continuity and locally square integrability of a function
- Bijection between $\Delta(A)$ and $\mathrm{Max}(A)$
- Exercise 1.105 of Megginson's "An Introduction to Banach Space Theory"
- Reference request for a lemma on the expected value of Hermitian polynomials of Gaussian random variables.
- If $A$ generates the $C_0$-semigroup $\{T_t;t\ge0\}$, then $Au=f \Rightarrow u=-\int_0^\infty T_t f dt$?
Related Questions in OPERATOR-ALGEBRAS
- Bijection between $\Delta(A)$ and $\mathrm{Max}(A)$
- hyponormal operators
- Cuntz-Krieger algebra as crossed product
- Identifying $C(X\times X)$ with $C(X)\otimes C(X)$
- If $A\in\mathcal{L}(E)$, why $\lim\limits_{n\to+\infty}\|A^n\|^{1/n}$ always exists?
- Given two projections $p,q$ in a C$^{*}$-algebra $E$, find all irreducible representations of $C^{*}(p,q)$
- projective and Haagerup tensor norms
- AF-algebras and K-theory
- How to show range of a projection is an eigenspace.
- Is $\left\lVert f_U-f_V\right\rVert_{op}\leq \left\lVert U-V\right\rVert_2$ where $f_U = A\mapsto UAU^*$?
Related Questions in C-STAR-ALGEBRAS
- Cuntz-Krieger algebra as crossed product
- Given two projections $p,q$ in a C$^{*}$-algebra $E$, find all irreducible representations of $C^{*}(p,q)$
- AF-algebras and K-theory
- How to show range of a projection is an eigenspace.
- Is a $*$-representation $\pi:A\to B(H)$ non-degenerate iff $\overline{\pi(A) B(H)} = B(H)$?
- Spectral theorem for inductive limits of $C^*$-Algebras
- Examples of unbounded approximate units in $C^*$-algebras
- Is there a way to describe these compactifications algebraically?
- Projections in C*-algebras
- Homogeneous C*-algebras
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?
Typical example is $A=M_2(\mathbb C)$, $$ a=\begin{bmatrix}1&0\\0&0\end{bmatrix},\ \ \ b=\begin{bmatrix}1/2&1/2\\ 1/2&1/2\end{bmatrix}. $$ Then $0\leq a\leq 1$, $0\leq b\leq 1$, but neither $ab$ nor $ba$ is selfadjoint.