Generalized Picard-Vessiot extensions and differential Galois cohomology
Abstract
In an earlier paper it was proved that if a differential field is algebraically closed and closed under Picard-Vessiot extensions then every differential algebraic principal homogeneous space over K for a linear differential algebraic group G over K has a K-rational point (in fact if and only if). This paper explores whether and if so, how, this can be extended to (a) several derivations, (b) one automorphism. Under a natural notion of "generalized Picard-Vessiot extension" (in the case of several derivations), we give a counterexample. We also have a counterexample in the case of one automorphism. We also formulate and prove some positive statements in the case of several derivations.
Keywords
Cite
@article{arxiv.1702.01969,
title = {Generalized Picard-Vessiot extensions and differential Galois cohomology},
author = {Zoe Chatzidakis and Anand Pillay},
journal= {arXiv preprint arXiv:1702.01969},
year = {2017}
}
Comments
The new version is the one accepted by Annales Math. Toulouse, and makes some clarifications and additions suggested by the referees, including reference to a recent related paper by Minchenko and Ovchinnikov