On some examples in the theory of power series
P. Túrán · Bulletin of the American Mathematical Society · 1948
October 7(^i> • • • f Vn) is contained in a liouvillian extension of J of the required type.It follows that rji, • • • , rj n is a fundamental system of solutions of L(y), and (see PV, §25) J(rji f • • • , rj n ) is itself a liouvillian extension of J of the required type.