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interested in representations of groups, algebraic groups, arithmetic groups, rigidity, and related automorphic forms. Recently interested in braid groups and configuration spaces.

Mar
29
comment Non existence of cyclic infinite linear algebraic groups
@Starr: another thing. The norm map is not like a valuation map. It rarely specializes, at the level of $L^*$ into $k^*$, as a map of $T'(k)$ onto $\mathbb Z$
Mar
29
comment Non existence of cyclic infinite linear algebraic groups
@Starr; No, that is not what I am doing. There is a finite kernel map from $T'$ into the anisotropic torus $T$ and a surjection from the anisotropic torus to $R^1({\mathbb G}_m=T'$; this implies that the group of norm one elements (if we assume $G(k)=\mathbb Z$) in $l^*$ is also $\mathbb Z$ up to finite kernel and cokernel; that is impossible.
Mar
29
comment Non existence of cyclic infinite linear algebraic groups
@Cornulier, Any such torus maps onto a torus f the form $T'=R^1_{l/k}({\mathbb G}_m$, and contains such an anisotropic torus $T'$. We need only prove it when $T'=T$, and this is really like the case $k^*$ (with a little more work.
Mar
29
revised Non existence of cyclic infinite linear algebraic groups
added 603 characters in body
Mar
29
comment Non existence of cyclic infinite linear algebraic groups
@Jason,thank you. All I am saying is that over $K$, the group is a product of mult and add groups (not over the smaller field $k$). The group of $k$ rational points, in case add factors are involved, cannot be $\mathbb Z$; in case only mult factors are involved, we will have to use that such a group, after multiplying by a suitable product of $R_{l/k}({\mathbb G }_m$, where $R$ iw thw Weil restriction of scalars.
Mar
28
reviewed Approve suggested edit on If y forms Pythagorean triples with two different x, can some other y also form Pythagorean triples with those two x?
Mar
28
revised Non existence of cyclic infinite linear algebraic groups
edited body
Mar
28
revised Non existence of cyclic infinite linear algebraic groups
gave some more detailsof the proof
Mar
28
answered Non existence of cyclic infinite linear algebraic groups
Mar
23
reviewed Approve suggested edit on Holomorphic vector field on Fano Kähler–Einstein manifold
Mar
14
answered Automorphism group of flag manifolds?
Mar
7
revised Does there exist a function such that $\int_{\mathbb{R}_+^{\star} } t^nf(t)dt=0$?
deleted 1 characters in body
Mar
6
reviewed Approve suggested edit on Erdős-Straus with 4 terms
Mar
3
comment Root space decomposition
This is discussed in Helgason's book on symmetric spaces.
Feb
23
answered abelian varieties with the same CM type are isogenous
Feb
18
reviewed Approve suggested edit on Twin Prime Conjecture Reference
Feb
14
awarded  Custodian
Feb
14
reviewed Approve suggested edit on Examples of non-split algebraic groups
Jan
27
comment Convergence of a Trigonometric Series
@Ethan,I think you should change it, stating what it is that you want; as it stands, Noam Elkies has answered the question.
Jan
26
revised Irreducible representations of compact groups
added 134 characters in body