Jacobian Nullwerte, Periods and Symmetric Equations for Hyperelliptic   Curves
  We propose a solution to the hyperelliptic Schottky problem, based on the use of Jacobian Nullwerte and symmetric models for hyperelliptic curves. Both ingredients are interesting on its own, since the first provide period matrices which can be geometrically described, and the second have remarkable arithmetic properties. 
J. Gu\`ardia