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5 votes
1 answer
212 views

States "absorbed" by a Haar idempotent on a compact quantum group

Firstly, a small question of nomenclature. If $(S,\bullet)$ is a magma, is there good terminology to relate $a$ to $b$ when $$a\bullet b=b=b\bullet a?$$ Can we say that $b$ absorbs $a$? Can we say ...
JP McCarthy's user avatar
  • 1,037
2 votes
1 answer
169 views

Action of a group $G$ induces a coaction on $C_0(G)$

In this question, I follow the book "An invitation to quantum groups and duality" by Timmerman, p259. Let $G$ be a locally compact group and $C$ be a $C^*$-algebra. Assume an action $$\alpha:...
Andromeda's user avatar
  • 175
4 votes
0 answers
165 views

Tensor product of representations on a compact quantum group

Let $\mathbb{G}$ be a $C^*$-algebraic compact quantum group (in the sense of Woronowicz) with function algebra $(C(\mathbb{G}), \Delta)$. Let $X \in M(B_0(H)\otimes C(\mathbb{G}))$ and $Y \in M(B_0(K)\...
Andromeda's user avatar
  • 175
2 votes
2 answers
217 views

Kernel of intertwiner is invariant (compact quantum groups)

Before asking my question, let me introduce the relevant terminology. Throughout, let $(A, \Delta)$ be a compact quantum group. Definition: A representation $v$ on the Hilbert space $H$ is an element $...
user avatar
0 votes
1 answer
158 views

Showing a product on a character space is continuous

Quoting from Timmermann's An invitation to quantum groups and duality: Prop. 5.1.3 Let $A$ be a commutative algebra of functions on a compact quantum group. Then there exists a compact group $G$ and ...
JP McCarthy's user avatar
  • 1,037
9 votes
0 answers
284 views

Verifying Woronowicz’s proof that all $ {\text{SU}_{q}}(2) $’s are isomorphic as $ C^{*} $-algebras, where $ -1 < q < 1 $

This question is related to one that I asked some time ago. Definition 1. Let $ q \in (-1,1) $. Let $ A $ be a unital $ C^{*} $-algebra and $ (x,y) $ a pair of elements of $ A $. Then define the $ ...
Transcendental's user avatar
4 votes
1 answer
414 views

A question on an argument in Woronowicz’s paper on the compact quantum group $ {\text{SU}_{q}}(2) $

Let $ q \in [0,1) $. The compact quantum group $ {\text{SU}_{q}}(2) $ is defined to be the universal unital $ C^{*} $-algebra that is generated by two elements $ \alpha $ and $ \beta $ satisfying the ...
Transcendental's user avatar
11 votes
1 answer
667 views

Compact Quantum Groups and the Existence of the Classical Haar Measure

Before I state my question, let me provide the definition of a compact quantum group. Definition: An ordered pair $ \mathscr{G} = (\mathscr{A},\Phi) $ is called a compact quantum group if $ ...
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