Takayuki Okuda

Degenerations of propeller surfaces and sequences of splittings


A propeller surface is a Riemann surface equipped with an automorphism
that behaves like rotation of a propeller.
In this talk, we consider degenerations of such propeller surfaces
and splittings of their singular fibers.
We show that the singular fibers with propeller monodromies
can split into Lefschetz fibers.  To be precise,
we construct sequences of deformations in each of which
a singular fiber splits into a simpler singular fiber and three Lefschetz
fibers.