Frederik Benirschke, Benjamin Dozier and Samuel
Grushevsky
Geometry & Topology 26 (2022) 2773–2830
DOI: 10.2140/gt.2022.26.2773
Abstract
We investigate the closure
of a linear subvariety
of a stratum of meromorphic differentials in the multiscale compactification constructed by
Bainbridge, Chen, Gendron, Grushevsky and Möller. Given the existence of a boundary
point of of
a given combinatorial type, we deduce that certain periods of the differential are pairwise
proportional on ,
and deduce further explicit linear defining relations. These restrictions on linear defining
equations of
allow us to rewrite them as explicit analytic equations in plumbing coordinates near the
boundary, which turn out to be binomial. This in particular shows that locally near the
boundary
is a toric variety, and allows us to prove existence of certain smoothings of boundary
points and to construct a smooth compactification of the Hurwitz space of covers of
. As
applications of our techniques, we give a fundamentally new proof of a generalization
of the cylinder deformation theorem of Wright to the case of real linear subvarieties
of meromorphic strata.
Keywords
Teichmüller dynamics, moduli of curves, flat surfaces