Speaker: Alex Fink, Queen Mary University of London
Title: Matrix orbit closures and their classes
Time: 2:30 PM, FRIDAY, October 11, 2019
Place: Malott 230
Abstract: If an ordered point configuration in projective space is represented
by a matrix of coordinates, the resulting matrix is determined up to
the action of the general linear group on one side and the torus of
diagonal matrices on the other. We study orbits of matrices under the
action of the product of these groups, as well as their images in
quotients of the space of matrices like the Grassmannian. The main
question is what properties of closures of these orbits are determined
by the matroid of the point configuration; the main result is that
their equivariant K-classes are so determined.
The results of mine are joint with Andy Berget, apart from some which
are instead joint with David Speyer.
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