14 citations · 61 across the 22 of their papers we have counts for
16 papers · 1 filter
Trivializing Torsors for Difference Algebraic Groups
Annette Bachmayr, Michael Wibmer
We study torsors for groups defined by algebraic difference equations. Our main result provides necessary and sufficient conditions on the base difference field for all such torsor…
The regular singular inverse problem in differential Galois theory
Thomas Serafini, Michael Wibmer
We show that every linear algebraic group over an algebraically closed field of characteristic zero is the differential Galois group of a regular singular linear differential equat…
On the proalgebraic fundamental group of topological spaces and amalgamated products of affine group schemes
Christopher Deninger, Michael Wibmer
The proalgebraic fundamental group of a connected topological space , recently introduced by the first author, is an affine group scheme whose representations classify local sys…
Regular singular differential equations and free proalgebraic groups
Michael Wibmer
We determine the differential Galois group of the family of all regular singular differential equations on the Riemann sphere. It is the free proalgebraic group on a set of cardina…
Differential Galois groups, specializations and Matzat's conjecture
Ruyong Feng, Michael Wibmer
We study families of linear differential equations parametrized by an algebraic variety and show that the set of all points , such that the differen…
A remark on torsors for affine group schemes
Michael Wibmer
We present an elementary proof of the fact that every torsor for an affine group scheme over an algebraically closed field is trivial. This is related to the uniqueness of fibre fu…