Filtrations of absolute Galois groups
A profinite group is equipped with various standard filtrations by closed normal subgroup,
such as the lower central series, the lower p-central series, and the p-Zassenhaus filtration.
In the case of an absolute Galois group of a field, these filtrations are related to the arithmetic
structure of the field, as well as with its Galois cohomology. We will describe some recent
results on these connections, in particular with the Massy product in Galois cohomology.