Sur la K-theorie du foncteur norme, by Max Karoubi and Thierry Lambre
The K-theory of a functor may be viewed as a relative version of the K-theory
of a ring. In the case of a Galois extension of a number field F/L with rings
of integers A/B respectively, this K-theory of the "norm functor" is an
extension of a subgroup of the ideal class group Cl(A) by the 0-Tate cohomology
group with coefficients in A*. The Mayer-Vietoris exact sequence enables us to
describe quite explicitly this extension which is related to the coinvariants
of Cl(A) under the action of the Galois group. We apply these ideas to find
results in Number Theory, which are known for some of them with different
methods.
Max Karoubi <karoubi@math.jussieu.fr>
Thierry Lambre <thierry.lambre@math.univ-bpclermont.fr>