If every irreducible polynomial in F[x] with a root in E has all of its roots in E, then E is called a normal extension of F; that is, every irreducible polynomial in...If every irreducible polynomial in F[x] with a root in E has all of its roots in E, then E is called a normal extension of F; that is, every irreducible polynomial in F[x] containing a root in E is the product of linear factors in E[x].