The aim of this paper is to provide a proof of the following result claimed by Albu (Infinite field extensions with Galois–Cogalois correspondence (II), Revue Roumaine Math. Pures Appl. 47 (2002), to appear): The Kneser group Kne (E/F) of an Abelian G-Cogalois extension E/F and the group of continuous characters Ch(Gal (E/F)) of its Galois group Gal (E/F) are isomorphic (in a noncanonical way). The proof we give in this paper explains why such an isomorphism is expected, being based on a classical result of Baer (Amer. J. Math.61 (1939), 1–44) devoted to the existence of group isomorphisms arising from lattice isomorphisms of their lattices of subgroups.
Solvable number field extensions of bounded root discriminant
