We study the relation between Galois group G of a linear difference-differential system and two classes C1 C2 groups that are specializations difference equation differential in this respectively. show almost all C1∪C2 algebraic subgroups G, there is nonempty subset such product any pair from these subsets. These results have potential application to computation system. also give criterion for ...

In this article we study exponential dichotomies for noninvertible linear difference equations in finite dimensions. After giving the definition, extent to which projection P(k) a dichotomy is unique. For on Z it unique but Z+ only its range and Z− nullspace. Here strengthen Kalkbrenner's results give complete characterization of all possible projections. Next possibility extending larger inter...