Difference algebra

Abstract: This ACM volume deals with tackling problems that can be represented by data structures which are essentially matrices with polynomial entries, mediated by the disciplines of commutative algebra and algebraic geometry. The discoveries stem from an interdisciplinary branch of research which has been growing steadily over the past decade. The author covers a wide range, from showing how to obtain deep heuristics in a computation of a ring, a module or a morphism, to developing means of solving nonlinear systems of equations - highlighting the use of advanced techniques to bring down the cost of computation. Although intended for advanced students and researchers with interests both in algebra and computation, many parts may be read by anyone with a basic abstract algebra course.

Abstract: The introduction of school algebra can take many different directions: the rules for transforming and solving equations (to which current teaching often reduces algebra), the solving of specific problems or classes of problems (which has played an important role historically in the development of algebra and its teaching), the generalization of laws governing numbers (a very strong focus in certain curricula), the more recent introduction of the concepts of variable and function (which appeared much later historically and which occupy a position of growing importance in some programs), and the study of algebraic structures (which marked the school curriculum in the 1960s under the influence of modern mathematics).

Abstract: Picard-Vessiot rings.- Algorithms for difference equations.- The inverse problem for difference equations.- The ring S of sequences.- An excursion in positive characteristic.- Difference modules over .- Classification and canonical forms.- Semi-regular difference equations.- Mild difference equations.- Examples of equations and galois groups.- Wild difference equations.- q-difference equations.