Intercity Seminar Number Theory
P. Stevenhagen
various places, 1999/2000
Seminar Algebra and Geometry
G. van der Geer
Amsterdam, 1999/2000
Intercity Seminar Algebraic Geometry
G. van der Geer, E. Looijenga, F. Oort
various places, Fall 1999
Topology Seminar
K.P. Hart, J. van Mill
Amsterdam & Delft, 1999/2000