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7 votes
1 answer
219 views

$*$-algebras, completions, and $K$-theory

What is an example of a $*$-algebra $\cal{A}$, which admits two non-equivalent norms $\| \cdot \|_1$ and $\| \cdot \|_2$, with respect to which we can complete $\cal{A}$ to give two $C^*$-algebras $...
Max Schattman's user avatar
6 votes
1 answer
446 views

A Question About the Elliott-Natsume-Nest Proof of Bott Periodicity

In Wegge-Olsen’s book K-Theory and C$ ^{*} $-Algebras, there is an outline of a proof of Bott Periodicity (the proof is due to George Elliott, Toshikazu Natsume and Ryszard Nest). The first step of ...
user avatar
2 votes
1 answer
352 views

K-Theory of $C^{*}(X)$

I'm new to K-Theory for $C^{*}$-algebra and $C^{*}$-algebra of groups. If $X$ is the group of finite support bijections of natural numbers then what is the K-Theory of $C^{*}(X)$? I was planning to ...
Peg Leg Jonathan's user avatar
2 votes
0 answers
208 views

A functor on the category of rings, algebras or compact Hausdorff topological space

Assume that $R$ is a unital ring or a complex or real (Banach or $C^{*}$) algebra. We define a relation $M$ on $R$ as follows: $$a\;M b \;\;\; \text{iff}\;\; a=xy,\;b=yx \;\; \text{for ...
Ali Taghavi's user avatar