On a Theorem of Ziv Ran concerning Abelian Varieties Which Are Product of Jacobians

الملخص EN

We give a new proof for a theorem of Ziv Ran which generalizes some results of Matsusaka and Hoyt.

These results provide criteria for an Abelian variety to be a Jacobian or a product of Jacobians.

The advantage of our method isthat it works in arbitrary characteristic.