On a quantitative refinement of the Lagrange spectrum
On Perrine's generalized Markoff equation.
On Perrine's generalized Markoff equations. (Summary).
On the closedness of approximation spectra
Generalizing Cusick’s theorem on the closedness of the classical Lagrange spectrum for the approximation of real numbers by rational ones, we prove that various approximation spectra are closed, using penetration properties of the geodesic flow in cusp neighbourhoods in negatively curved manifolds and a result of Maucourant [Mau].
On the Gaps of the Markoff Spectrum.
On the greatest prime factor of Markov pairs
On the inhomogeneous Hall's ray of period-one quadratics.