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Kac-Moody groups, hovels and Littelmann paths

Stéphane Gaussent, Guy Rousseau (2008)

Annales de l’institut Fourier

We give the definition of a kind of building for a symmetrizable Kac-Moody group over a field K endowed with a discrete valuation and with a residue field containing . Due to the lack of some important property of buildings, we call it a hovel. Nevertheless, some good ones remain, for example, the existence of retractions with center a sector-germ. This enables us to generalize many results proved in the semisimple case by S. Gaussent and P. Littelmann. In particular, if K = ( ( t ) ) , the geodesic segments...

Macdonald formula for spherical functions on affine buildings

A. M. Mantero, A. Zappa (2011)

Annales de la faculté des sciences de Toulouse Mathématiques

In this paper we explicitly determine the Macdonald formula for spherical functions on any locally finite, regular and affine Bruhat-Tits building, by constructing the finite difference equations that must be satisfied and explaining how they arise, by only using the geometric properties of the building.

On the Haagerup inequality and groups acting on A ˜ n -buildings

Alain Valette (1997)

Annales de l'institut Fourier

Let Γ be a group endowed with a length function L , and let E be a linear subspace of C Γ . We say that E satisfies the Haagerup inequality if there exists constants C , s > 0 such that, for any f E , the convolutor norm of f on 2 ( Γ ) is dominated by C times the 2 norm of f ( 1 + L ) s . We show that, for E = C Γ , the Haagerup inequality can be expressed in terms of decay of random walks associated with finitely supported symmetric probability measures on Γ . If L is a word length function on a finitely generated group Γ , we show that,...

On the loop inequality for euclidean buildings

Jacek Świątkowski (1997)

Annales de l'institut Fourier

We give an estimate for the number of closed loops of given length in the 1-skeleton of a thick euclidean building. This kind of estimate can be used to prove the (RD) property for the subspace of radial functions on A ˜ n groups, as shown in the paper by A. Valette [same issue].

On Veldkamp lines.

Shult, Ernest (1997)

Bulletin of the Belgian Mathematical Society - Simon Stevin

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