Jan-Hendrik Evertse       Universiteit Leiden Mathematisch Instituut Number theory group   E-mail:  evertse@math.leidenuniv.nl Preprints/publications Curriculum vitae Conference lectures Courses Bachelor projects Editorial work Organized workshops Research interests Links Compositio Math.                   Mailing address: Universiteit Leiden Mathematisch Instituut        Postbus 9512 2300 RA  Leiden The Netherlands   Visiting address: Snellius Niels Bohrweg 1 2333 CA Leiden Office: 248 (3rd floor) Tel: +31 (0)71 5277148 Fax: +31 (0)71 5277101   Home address: Filips van Bourgondiëstraat 41 3117 SC  Schiedam Tel: +31 (0)10 4263847 Next page  >>> OPEN PROBLEMS (posed at the Instructional conference and workshop "Solvability of Diophantine equations", May 7-16, 2007, Lorentz Center, Leiden).