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seen Dec 16 at 19:17

Aug
11
comment Existence of proper I.C.C. subgroup
Thanks for your quick answer, do you know any I.C.C. non amenable inner amenable groups satisfy this property?
Aug
11
accepted Existence of proper I.C.C. subgroup
Aug
11
comment Existence of proper I.C.C. subgroup
I do not understand why "g is contained in two separate cyclic subgroups". I think the following argument also works. Clearly, we can pick some $h_i$ with $h_i\not\in \langle g\rangle$ then $\langle h_i, g\rangle=T$ so $T$ is abelian, a contradition.
Aug
11
revised Question on amenable direct summand
add more assumption
Aug
11
comment Compact operators on $L^2(G)$ as a reduced cross product of $C_0(G)$ and $G$.
Why $\mathbb{C}1 \otimes C^*(\pi(c_0(G)), \{\lambda_g : g \in G\}) \cong \mathcal{K}(\ell^2(G))$? And a first feeling is that $\lambda_g$ is not a compact operator.
Aug
11
asked Existence of proper I.C.C. subgroup
Aug
11
comment Almost everywhere measurable homomorphism
Could you give any reference for this result?
Aug
4
asked Question on extension of cocycles
Jul
27
comment Why is the natural map from maximal to reduced C star algebra surjective?
I see, the second fact you mentioned is also used to show $||.||_{max}$ is the largest norm on algebraic tensor of two C star algebras, thanks a lot!
Jul
27
accepted Why is the natural map from maximal to reduced C star algebra surjective?
Jul
26
comment Question on amenable direct summand
Oops, sorry, I should have mentioned $A\subset B\subset N$.
Jul
26
revised Question on amenable direct summand
Fix missing condition
Jul
26
asked Why is the natural map from maximal to reduced C star algebra surjective?
Jul
26
asked Question on amenable direct summand
Jul
21
accepted find element in relative commutant of a matrix subalgebra
Jul
19
comment find element in relative commutant of a matrix subalgebra
Thanks, I realized that the basic idea is to integral over the unitary group of $M_2(\mathbb{C})$ of $uau^{*}$, matrix units seems to play the role of unitary.
Jul
19
revised find element in relative commutant of a matrix subalgebra
fix typos
Jul
19
answered find element in relative commutant of a matrix subalgebra
Jul
19
asked find element in relative commutant of a matrix subalgebra
Jul
9
comment Short exact sequence involving mapping cone, cone, suspension of $C^*$-algebras
Do we have a natural morphism from SB to SA?