Ramification and semistable abelian varieties

In this thesis we classify completely almost rational torsion points on semistable elliptic curves. We also generalize theorems of Fontaine, Schoof, and Brumer-Kramer, and determine for which N there exist semistable abelian varieties A/$Q$ which have smooth models over $Z$[1/N]. Our results on semistable abelian varieties with good reduction almost everywhere depend on the Generalized Riemann Hypothesis discriminant bounds of Odlyzko.