Quadratic irrationals, ambiguous classes and symmetry in real quadratic fields
R. A. Mollin · Proceedings of the Japan Academy Series A Mathematical Sciences · 1994
It is the purpose of this paper to set down the relationship between symmetry in the continued fraction expansion of a quadratic irra- tional, and the number of ambiguous ideals in an associated class of the class group of a real quadratic field.We also clear up some misconceptions in the literature pertaining to ambiguous classes.