Colloquium
3:30 p.m., Friday (Sept. 29)
Math 100
Ravi Vakil
M.I.T.
Branched covers of the sphere and the moduli space of curves:
Geometry, physics, representation theory, combinatorics
The moduli space of curves has been a central tool and object of study in
algebraic geometry for many decades, and yet its topology (and
intersection theory) has proved remarkably difficult to understand,
despite the belief that much of it is in some sense combinatorial.
Recent developments in GromovWitten theory have established a connection
between intersection theory on the moduli space of curves and branched
covers of the sphere, bringing to bear ideas from the fields of
mathematics mentioned in the title.
I'll describe the moduli space of pointed curves, Witten's conjecture
(Kontsevich's theorem), Faber's conjecture, and the Virasoro conjecture,
and discuss some of the developments in the area (both old and new), and
future prospects. Despite the subject matter, most of the talk will be
accessible to a wide audience.
