\contentsline {section}{\numberline {1}The circle pairing}{2}
\contentsline {section}{\numberline {2}Derived periods}{5}
\contentsline {section}{\numberline {3}The conjecture}{12}
\contentsline {section}{\numberline {4}Numerical evidence}{15}
\contentsline {section}{\numberline {5}A Gross-Kohnen-Zagier formula}{18}