Mathematics colloquium
Speaker: Mikhail Zaidenberg (University of Grenoble)
Title: Flexible varieties and automorphisms groups
Time: Monday, April 16, 3:30 pm
Place: Amado 232, Technion
Abstract: Given an affine algebraic variety X of dimension n ~I
2, we let SAut(X ) denote the special automorphism group of X i.e.,
the subgroup of the full automorphism group Aut(X ) generated by all
one-parameter unipotent subgroups. We show that if SAut(X )
is transitive on the smooth locus Xreg of X then it is infinitely
transitive on Xreg . In turn, the transitivity is equivalent to the
~Bexibility of X . The latter means that for every smooth point x
~H~H Xreg the tangent space Tx X is spanned by the velocity vectors
at x of one-parameter unipotent subgroups of Aut(X ). We provide
different applications and examples. This is a report on a joint
work with Ivan Arzhantsev, Hubert Flenner, Shulim Kaliman, Karine
Kuyumzhiyan, and Frank Kutzschebauch.
Colloquium Homepage: 
Technion Math. Net (TECHMATH)
Editor: Michael Cwikel   <> 
Announcement from: Amir Yehudayoff   <>