Alguns resultados sobre o grupo das classes dos corpos quadráticos

Abstract

Many are the known results involving the groups of numbers elds and many are the open problems. We know that the group of classes of a number fields is finite and abelian. In this paper we present some results about the group of the classes of the quadratic fields. It is known that for every intergers n greater than zero there are finite quadratic fields, both real and imaginary, whose class groups have a cyclic subgroup of order n. For an arbitrary abelian group G of order n, the existence or not of finite quadratic fields with groups of ideal classes having a subgroup isomorphic to G is an open problem. Particularly for non-cyclic finite abelian groups G, Kwang-Seob Kim has proved that there are finite real quadratic bodies in G =Z/nZ x Z/nZ: Whose groups of ideal classes contains a subgroup isomorphic to G and that is G = Z/nZ x Z/nZxZ/nZ then there are finite imaginary quadratic cups whose groups of ideal classes contain a subgroup isomorphic to G. The theorem of Kwang-Seob Kim is the main result presented in this dissertation.