The inverse problem of differential Galois theory over the field R(z)
arXiv:0802.2897
Abstract
We describe a Picard-Vessiot theory for differential fields with non algebraically closed fields of constants. As a technique for constructing and classifying Picard-Vessiot extensions, we develop a Galois descent theory. We utilize this theory to prove that every linear algebraic group over occurs as a differential Galois group over . The main ingredient of the proof is the Riemann-Hilbert correspondence for regular singular differential equations over .
23 pages