On the sum of two integral squares in certain quadratic fields
arXiv:1005.0658
Abstract
In this note, we give a necessary and sufficient condition for determining which integers can be written as a sum of two integral squares for certain quadratic fields by using the integral Brauer-manin obstruction (see \cite{CTX}). The condition is computable and originally from the reciprocity law.
16 pages,Forum Math.(to appear)