On a theorem of Serret on continued fractions
arXiv:1301.5944
Abstract
A classical theorem in continued fractions due to Serret shows that for any two irrational numbers x and y related by a transformation in PGL(2,Z) there exist s and t for which the complete quotients x_s and y_t coincide. In this paper we give an upper bound in terms of for the smallest indices s and t.