The parameterized Picard-Vessiot theory aims at studying the differential behavior of solutions of parameterized linear differential equations. It associates to such an equation a linear differential algebraic group (LDAG), that is, a group of matrices whose entries are functions satisfying a fixed set of differential equations. After giving an introduction to this theory, I will show that not all LDAGs can occur as Galois groups over k(x), the field of rational functions in x whose coefficients are functions of a parameter t and characterize those LDAGs that do occur.
- Séminaire Géométrie et théorie des modèles