On the quadratic Lagrange spectrum
نویسنده
چکیده
We study the quadratic Lagrange spectrum defined by Parkkonen and Paulin by considering the approximation by elements of the orbit of a given real quadratic irrational number for the action by homographies and anti-homographies of PSL2(Z) on R ∪ {∞}. Our approach is based on the theory of continued fractions.
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