Die Kreisklassenkörper von Primzahlpotenzgrad und die Konstruktion von Körpern mit vorgegebener zweistufiger Gruppe. I.
A “Galois theory” of differential equations was first proposed by Émile Picard in 1883. Picard, then a young mathematician in the course of making his name, sought an analogue to Galois’s theory of polynomial equations for linear differential equations with rational coefficients. His main results were limited by unnecessary hypotheses, as was shown in 1892 by his student Ernest Vessiot, who both improved Picard’s results and altered his approach, leading Picard to assert that his lay closest to...
An effective construction of homogeneous linear differential equations of order 2 with Galois group or is presented.
In this paper we study the formal differential Galois group of linear differential equations with coefficients in an extension of by an exponential of integral. We use results of factorization of differential operators with coefficients in such a field to give explicit generators of the Galois group. We show that we have very similar results to the case of .