Let K = ℚ(,),
where d1 and d2 are positive square-free integers such that (d1,d2) = 1. Let
K2(1) be the Hilbert 2-class field of K. Let K2(2) be the Hilbert 2-class field
of K2(1) and K(∗) the genus field of K. We suppose that K2(1)≠K(∗) and
Gal(K2(1)∕K) ≃ ℤ∕2ℤ × ℤ∕2ℤ. We study the capitulation problem of the 2-ideal
classes of K in the sub-extensions of K2(1)∕K and we determine the structure of
Gal(K2(2)).
Keywords
groupe de classes, capitulation, corps de classes de
Hilbert