arXiv subjects
Publications and source records attributed to Kay Wingberg.
We introduce the notion of saturated sets of primes of an algebraic number field and prove an analogue of Riemann's existence theorem for the decomposition groups of infinite stably saturated sets of primes.
We introduce the notion of corestricted free products of a family of profinite groups indexed over an arbitrary profinite space. Using arithmetic results of the second author, this enables us to prove an analogue of Riemann's existence theorem for the decomposition groups of certain infinite sets of primes of a number field.
We study the group of ends of a pro-p group G and prove a pro-p analog of Stallings' decomposition theorem.
We show that the class of profinite duality groups is closed under group extensions provided that the kernel satisfies some finiteness condition. This extends earlier results of Pletch and of Wingberg.
In this paper we consider pro-p Poincaré groups of dimension 2 (so-called Demuskin groups) on which a finite (abelian) group of order prime to p acts. In particular, we are interested in free pro-p quotient which are invariant under this action.
In this paper we define a topology with sufficiently good properties on the set of prime ideals of a number field.
Fontaine and Mazur conjecture that a number field k has no infinite unramified Galois extension such that its Galois group is a p-adic analytic pro-p-group. We consider this conjecture for the maximal unramified p-extension of a CM-field k.
In this paper we present a complete proof of I.R.Safarevic's famous theorem that every finite solvable group occurs as a Galois group over Q.