6,587 reputation
1935
bio website www2.unine.ch/alain.valette
location Neuchâtel, Switzerland
age 55
visits member for 3 years
seen 1 hour ago

1h
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
comment 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
comment Reflexive (hyperbolic) graphs
I see. Thanks for clarifying.
Jan
8
comment 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
comment 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
comment 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
comment 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
comment Le Gall's equivariant KK-theory and twisted equivariant KK-theory
Have you tried this? portico.org/Portico/browse/access/…
Jan
6
comment Why we need to study representations of matrix groups?
This would be a good question for MathStackExchange.
Jan
3
comment 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 $z\mapsto -z$).
Dec
23
comment $Z_{2}$- graded structures for $C_{red} ^{*} (F_{2})$
Have you considered the $\mathbb{Z}_2$-grading associated with the involutive automorphism of $F_2$ obtained by flipping the generators?
Dec
23
comment Crossed Products by Permutation Groups
Yes, edited, thanks!
Dec
23
revised Crossed Products by Permutation Groups
edited body
Dec
23
answered Crossed Products by Permutation Groups