Embedding Galois problems and reduced norms

Abstract

For certain embedding problems $\tilde{G} \rightarrow G \simeq \operatorname{Gal}(L\mid K)$ associated to a representation $t: G \rightarrow \operatorname{Aut} A$ of the group G by automorphisms of a central simple K-algebra A of dimension n2, we prove that the solutions are the fields L((rN(z))1/n), with r running over K*/K* n and N(z) the reduced norm of an invertible element z in the algebra B ⊗ L, for B the twisted algebra of A by t.