KdV Institute
SYMPOSIUM ON THE OCCASION OF IAN MACDONALD'S
HONORARY DOCTORATE DEGREE AT THE UVA
The symposium will be held on Friday January 11 (2002) at lecture room
P227, Plantage Muidergracht 24 (gebouw Euclides), Amsterdam.

The symposium is organized to celebrate the honorary degree that the
Universiteit van Amsterdam will grant Ian Macdonald on Januari 8 for his
remarkable contributions to Lie group theory and the theory of special functions.

Organizers of the symposium: Tom H. Koornwinder (thk@science.uva.nl) and
Eric M. Opdam (opdam@science.uva.nl). 

TENTATIVE PROGRAM
  • 11.15-12.15 I.G. Macdonald (Queen Mary and Westfield college): Where it all came from.
  • 14.00-15.00 T.A. Springer (Universiteit van Utrecht): The Bruhat order of a group compactification.
  • 15.30-16.30 G.J. Heckman (Universiteit van Nijmegen); The exceptional geometry of the moduli space of quartic curves.
  • 16.30-16.45 Concluding words by T.H.Koornwinder.
  • 16.45 Drinks.

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    ABSTRACTS
     

  • I.G. Macdonald: A personal account of the history of product identities and related subjects.

    •  
  • T.A. Springer: An adjoint semisimple group G has a "wonderful" compactification X, which is

    • a smooth projective variety on which GxG acts. Let B be a Borel subgroup of G. Then BxB has
    finitely many orbits in X. The set of these orbits carries a "Bruhat order", defined by inclusion of
    orbit closures. This ordered set will be discussed in the talk.
     
  • G.J. Heckman: A smooth quartic curve in the plane has 28 bitangents, and the symmetry of this

    • line configuration is governed by the Weyl group of type E_7. These are results with a long
    history going back to the 19th century.
    Of more recent times are two locally hermitian symmetric structures
    on the moduli space of quartics, both connected with the affine root
    system of type E_7. One is flat and due to Looijenga (1981,1997). The
    other is hyperbolic and due independently to van Geemen (unpublished)
    and Kondo (2000).
    All 3 pictures have their own compactification techniques: GIT in the
    geometric picture, toroidal compactification in the flat picture, and
    Baily-Borel compactification in the hyperbolic picture. A good deal of
    the talk is concerned with a discussion of the birational relation
    between the 3 pictures.