Discretely shrinking targets in moduli space
Given a decreasing family B1⊃B2⊃⋯ of targets in a measure space X equipped with a flow φt (or transformation), the shrinking target problem asks to characterize when there is a full measure set of points x that hit the targets infinitely often in the sense that {n∈N∣φn(x)∈Bn} is unbounded.
This talk will examine the discrete shrinking target problem for the Teichmüller flow on the moduli space of unit-area quadratic differentials. Specifically, for any nested sequence of measurable sets Bi in the moduli space of Riemann surfaces with preimages Ei in quadratic differential space, consider the set H of unit-area quadratic differentials that hit the targets Ei infinitely often. We show that for any SL(2,R)--invariant probability measure μ, the set H has zero measure if {μ(Ei)} is summable and otherwise has full measure. As an application, we obtain logarithm laws describing how quickly a generic trajectory {φn(q)∣n∈N} accumulates on a given point. Joint with Grace Work.