Let A=A$_g, 1, n$ denote the moduli scheme over Z[1/N] of p.p. g-dimensional abelian varieties with a level n structure; its generic fibre can be described as a Shimura variety. We study its ’Shimura subvarieties‘. If x ∈ A is an ordinary moduli point in characteristic p, then we formulate a local ’linearity property‘ in terms of the Serre–Tate group structure on the formal deformation space (= formal completion of A at x). We prove that an irreducible algebraic subvariety of A is a ’Shimura subvariety‘ if, locally at an ordinary point x, it is ’formally linear‘. We show that there is a close connection to a differential-geometrical linearity property in characteristic 0.

We apply our results to the study of Oort‘s conjecture on subvarieties Z [rarrhk ] A with a dense collection of CM-points. We give a reformulation of this conjecture, and we prove it in a special case.

In this paper we study the trivial zero of the p-adic L function of the symmetric square of an elliptic curve and generalize a conjecture of Greenberg. For that, we use the new approach to p-adic L functions introduced in a previous work.

Let X be a strongly pseudoconvex compact 3-dimensional CR manifolds which bounds a complex variety with isolated singularities in some C$^N$. The weighted dual graph of the exceptional set of the minimal good resolution of V is a CR invariant of X; in case X has a tranversal holomorphic S¹ action, we show that it is a complete topological invariant of except for two special cases. When X is a rational CR manifolds, we give explicit algebraic algorithms to compute the graph invariant in terms of the ring structure of [oplus ]$_k=0$$^$∞ m$^k$/m$^k+1$, where m is the maximal ideal of each singularity. An example is computed explicitly to demonstrate how the algorithms work.