ABSTRACT
Cogalois Theory has nice applications to algebraic number fields. This chapter presents some of them. After reviewing, in Section 9.1, the standard notation, notions, and facts on algebraic number fields which will be used in the sequel, we show, in Section 9.2, that some classical results due to Hasse, Besicovitch, Mordell, Siegel are immediate consequences of basic facts in Cogalois Theory.
