A fundamental result in number theory is that, under certain linear actions of arithmetic groups on homogeneous varieties, the integral points of the varieties decompose into finitely many orbits.

For a classical example, the set of integral binary quadratic forms of fixed nonzero discriminant consists of finitely many orbits under action of the modular group SL2(Z).

In this talk, we discuss certain classes of algebraic varieties with inherently nonlinear group actions, for which analogous finite generation results for integral points can be established or conjectured.

These varieties arise as various moduli spaces (of local systems on surfaces, Stokes matrices, etc.) in geometry and topology of manifolds, allowing application of external tools to the study of Diophantine problems; the latter will be emphasized in the talk.