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Concept

Sous-groupe compact maximal

Publications associées (12)

Multiplicity-free Representations of Algebraic Groups

Donna Testerman

Let K be an algebraically closed field of characteristic zero, and let G be a connected reductive algebraic group over K. We address the problem of classifying triples (G, H, V ), where H is a proper connected subgroup of G, and V is a finitedimensional ir ...

Amer Mathematical Soc2024

Maximal subgroups acting with two composition factors on irreducible representations of exceptional algebraic groups

Nathan Scheinmann

Let

Y

be a simply connected simple algebraic group over an algebraically closed field

k

of characteristic

p

and let

X

be a maximal closed connected simple subgroup of

Y

. Excluding some small primes in specific cases, we classify the

p

-restrict ...

EPFL2019

Reductive overgroups of distinguished unipotent elements in simple algebraic groups

Mikko Tapani Korhonen

Let

G

be a simple linear algebraic group over an algebraically closed field

K

of characteristic

p \geq 0

. In this thesis, we investigate closed connected reductive subgroups

X < G

that contain a given distinguished unipotent element

u

G

. Our ...

EPFL2018

On irreducible subgroups of simple algebraic groups

Donna Testerman, Claude Marion

Let G be a simple algebraic group over an algebraically closed field K of characteristic p >= 0, let H be a proper closed subgroup of G and let V be a nontrivial irreducible KG-module, which is p-restricted, tensor indecomposable and rational. Assume that ...

Springer Heidelberg2017

Toda frames, harmonic maps and extended Dynkin diagrams

Katharine Felicity Turner

We consider a natural subclass of harmonic maps from a surface into G/T, namely cyclic primitive maps. Here G is any simple real Lie group (not necessarily compact), T is a Cartan subgroup and both are chosen so that there is a Coxeter automorphism on G(C) ...

Elsevier2017

Restricting representations of classical algebraic groups to maximal subgroups

Mikaël Cavallin

Fix an algebraically closed field

K

having characteristic

p\geq 0

and let

Y

be a simple algebraic group of classical type over

K.

Also let

X

be maximal among closed connected subgroups of

Y

and consider a non-trivial

p

-restricted irreducible ...

EPFL2015

Subgroups Of Simple Algebraic Groups Containing Regular Tori, And Irreducible Representations With Multiplicity 1 Non-Zero Weights

Donna Testerman

Our main goal is to determine, under certain restrictions, the maximal closed connected subgroups of simple linear algebraic groups containing a regular torus. We call a torus regular if its centralizer is abelian. We also obtain some results of independen ...

Springer Verlag2015

On the irreducibility of symmetrizations of cross-characteristic representations of finite classical groups

Donna Testerman

Let W be a vector space over an algebraically closed field k. Let H be a quasisimple group of Lie type of characteristic p not equal char(k) acting irreducibly on W. Suppose also that G is a classical group with natural module W, chosen minimally with resp ...

2013

Sequences with Minimal Time-Frequency Spreads

Martin Vetterli, Yann Barbotin, Reza Parhizkar

For a given time or frequency spread, one can always find continuous- time signals, which achieve the Heisenberg uncertainty principle bound. This is known, however, not to be the case for discrete-time sequences; only widely spread sequences asymptoticall ...

Ieee2013

Decomposing locally compact groups into simple pieces

Nicolas Monod

We present a contribution to the structure theory of locally compact groups. The emphasis is put on compactly generated locally compact groups which admit no infinite discrete quotient. It is shown that such a group possesses a characteristic cocompact sub ...

Cambridge University Press2011

Irreducibility of disconnected subgroups of exceptional algebraic groups

Soumaïa Nadia Ghandour

This dissertation is concerned with the study of irreducible embeddings of simple algebraic groups of exceptional type. It is motivated by the role of such embeddings in the study of positive dimensional closed subgroups of classical algebraic groups. The ...

EPFL2008

Extrapolation et synthèse

Christian Fiorillo

Let G a locally compact group, H a closed subgroup and 1 < p < ∞. It's well-known that the restriction of the functions from G to H is a surjective linear contraction from Ap(G) onto Ap(H). We prove, when H is amenable, that every element in Ap(H) with com ...

EPFL2007