Weylgruppe und Momentabbildung

Summary Let G be a connected, reductive group defined over an algebraically closed field of characteristic zero. We assign to any G-variety X a finite cristallographic reflection group W _X by means of the moment map on the cotangent bundle. This generalizes the little Weyl group of a symmetric space. The Weyl group W _X is related to the equivariant compactification theory of X. We determine the closure of the image of the moment map and the generic isotropy group of the action of G on the cotangent bundle. As a byproduct we determine the ideal of elements of (g) which act trivially on X as a differential operator.

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Teilweise unterstützt durch den Schweizerischen Nationalfonds