Liouvillian Solutions of Difference-Differential Equations
arXiv:0810.1574
Abstract
For a field kwithanautomorphismσandaderivationδ,weintroducethenotionofliouvilliansolutionsoflineardifference−differentialsystemsσ(Y)=AY,δ(Y)=BYoverkandcharacterizetheexistenceofliouvilliansolutionsintermsoftheGaloisgroupofthesystems.Wewillgiveanalgorithmtodecidewhethersuchasystemhasliouvilliansolutionswhenk=C(x,t),σ(x)=x+1,δ=d/dt and the size of the system is a prime.