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9 votes
1 answer
521 views

Which group algebras in analysis are "true group algebras"?

Let $G$ be a group, $A$ a unital associative algebra over ${\mathbb C}$, and let us call a representation of $G$ in $A$ an arbitrary map $\pi:G\to A$ such that $$ \pi(1)=1,\qquad \pi(a\cdot b)=\pi(a)\...
Sergei Akbarov's user avatar
8 votes
1 answer
808 views

Strong Morita equivalence and representation theory

In the context of pure algebra we say that two algebras (in general: rings) $A,B$ are Morita equivalence when there are bimodules $_AP_B,_BQ_A$ such that $P \otimes_B Q \cong _AA_A$ and $Q \otimes_A P ...
truebaran's user avatar
  • 9,330
8 votes
0 answers
251 views

When does a semisimple $\mathbb{C}$-algebra come from a group?

Let $\mathcal{A}$ be a semisimple $\mathbb{C}$-algebra. By the Artin-Wedderburn theorem, it is isomorphic to a direct product of matrix algebras: $$ \mathcal{A} = \prod_{i=1}^m M_{n_i}(\mathbb{C})$$ ...
pitariver's user avatar
  • 297
5 votes
1 answer
254 views

Well defined Tensoring of spectral triples

Hi, I have a misunderstanding that I am hoping is really quite trivial. I will give my question directly and context below for those that need/want it. Question: In connes standard model he takes ...
SMF's user avatar
  • 133
1 vote
1 answer
178 views

Representation of algebras as bounded nilpotent operators

Let $A$ be a real/complex algebra (just a real/complex vector space with a multiplication; none PI's are required). Let $\mathcal{H}$ be a real/complex Hilbert space. Let $\operatorname{B}(\mathcal{H})...
Math-Phys-Cat Group's user avatar