bio | website | www2.unine.ch/alain.valette |
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location | Neuchâtel, Switzerland | |
age | 55 | |
visits | member for | 3 years, 3 months |
seen | Jul 16 at 20:09 | |
stats | profile views | 4,343 |
Jul 2 |
awarded | Curious |
May 29 |
comment |
quantum states and observables for the non-commutative torus
$A_\theta$ can be obtained as the $C^*$-algebra generated by two unitaries on $\ell^2(\mathbb{Z}^2)$ associated with the formulation of the problem of the Bloch electron (describe the motion of a free electron on the square lattice submitted to a uniform magnetic field orthogonal to the lattice). See a famous paper by D. Hofstadter: zimp.zju.edu.cn/~xinwan/qm2/note/… |
Apr 28 |
revised |
Spectral gap of unitary representation
Precision added |
Apr 28 |
answered | Spectral gap of unitary representation |
Apr 18 |
awarded | Yearling |
Feb 20 |
awarded | Enlightened |
Feb 20 |
awarded | Nice Answer |
Jan 25 |
answered | Learning about Lie groups |
Jan 23 |
comment |
Why aren't fields called “bodies” instead?
A remark on local versions of french: the Belgians use "champ" (= field) for "corps commutatif", while the Swiss say as the French... |
Jan 19 |
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A question on lie groups( Lie algebras)
Take Sasha's example, and embed it into the simple Lie group $SU(3)$ (where $\mathbb{T}^2$ embeds as a maximal torus). |
Jan 12 |
answered | Modern Mathematical Achievements Accessible to Undergraduates |
Jan 8 |
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Reflexive (hyperbolic) graphs
I see. Thanks for clarifying. |
Jan 8 |
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Reflexive (hyperbolic) graphs
Why are you using "hyperbolic" in the title? (for me, hyperbolic graphs are graphs which are hyperbolic when viewed as metric spaces, which seems irrelevant to your question...) |
Jan 8 |
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Which groups are the unitary group of a $C^*$-algebra
You might also take the reduced C*-algebra. But in my view it says nothing about the OP (with due respect). |
Jan 6 |
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Why we need to study representations of matrix groups?
@Andy: I agree that the question produced some good answers. On the other hand, this basic question should be answered in any introductory book in representation theory (even if it is not always so, unfortunately...) |
Jan 6 |
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Le Gall's equivariant KK-theory and twisted equivariant KK-theory
If you succeed in getting a copy of Le Gall's thesis (probably available from Le Gall), I sort of remember that it is more detailed than the paper... |
Jan 6 |
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Le Gall's equivariant KK-theory and twisted equivariant KK-theory
Have you tried this? portico.org/Portico/browse/access/… |
Jan 6 |
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Why we need to study representations of matrix groups?
This would be a good question for MathStackExchange. |
Jan 3 |
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On an asymptotic in Sarnak's book: “Some applications of modular forms”
Thanks Igor, we owe you a beer now! |
Dec 23 |
comment |
$Z_{2}$- graded structures for $C_{red} ^{*} (F_{2})$
For $C(S^1)$, you also have the grading associated to the automorphism $z\mapsto z^{-1}$ of $S^1$ (viewed as the group of complex numbers of modulus one). The sub-algebra of elements of degree 0, is isomorphic to $C[-1,1]$, proving that this grading is not isomorphic to the one by even/odd functions (which is associated to $z\mapsto -z$). |