With the exception of a finite set of finite differential Galois group
s, if an irreducible linear differential equation L(y) = 0 of prime or
der with unimodular differential Galois group has a Liouvillian soluti
on, then all algebraic solutions of smallest degree of the associated
Riccati equation are solutions of a unique minimal polynomial. If the
coefficients of L(y) = 0 are in Q(alpha)(x) subset of (Q) over bar(x)
this unique minimal polynomial is also defined over Q(alpha)(x). In th
e finite number of exceptions all solutions of L(y) = 0 are algebraic
and in each case one can apriori give an extension Q(beta)(x) over whi
ch the minimal polynomial of an algebraic solution of L(y) = 0 can be
computed.