Mazur [8] has introduced the concept of visible elements in the Tate-Shafarevich group of optimal modular elliptic curves. We generalized the notion to arbitrary abelian subvarieties of abelian varieties and found, based on calculations that assume the BirchSwinnerton-Dyer conjecture, that there are elements of the Tate-Shafarevich group of certain sub-abelian varieties of J0(p) and J1(p) that ...

We classify the possible Mumford-Tate groups of polarizable rational Hodge structures.

We prove that for abelian varieties with semistable ordinary reduction the p-adic Mazur-Tate height pairing is induced by the unit root splitting of the Hodge filtration on the first deRham cohomology.

We improve Kolyvagin’s upper bound on the order of the p-primary part of the Shafarevich-Tate group of an elliptic curve of rank one over a quadratic imaginary field. In many cases, our bound is precisely the one predicted by the Birch and Swinnerton-Dyer conjectural formula.

Kolyvagin used Heegner points to associate a system of cohomology classes to an elliptic curve over Q and conjectured that the system contains a non-trivial class. His conjecture has profound implications on the structure of Selmer groups. We provide new computational and theoretical evidence for Kolyvagin’s conjecture. More precisely, we explicitly compute Heegner points over ring class fields...

This is an introduction to classical descent theory, in the context of abelian varieties over number fields.

We study monodromy action on abelian varieties satisfying certain bad reduction conditions. These conditions allow us to get some control over the Galois image. As a consequence we verify the Mumford–Tate conjecture for such abelian varieties.

Magnetization switching at the interface between ferromagnetic and paramagnetic metals, controlled by current-induced torques, could be exploited in magnetic memory technologies. Compelling questions arise regarding the role played in the switching by the spin Hall effect in the paramagnet and by the spin-orbit torque originating from the broken inversion symmetry at the interface. Of particula...