Electronic Thesis and Dissertation Repository

Algorithms for Regular Chains of Dimension One

Juan P. Gonzalez Trochez, The University of Western Ontario

Abstract

One of the core commands in the RegularChains library inside Maple is Triangularize. The underlying decomposes the solution set of a polynomial system into geometrically meaningful components represented by regular chains. This algorithm works by repeatedly calling a procedure, called Intersect, which computes the common zeros of a polynomial p and a regular chain T .

As the number of variables of p and T , as well as their degrees, increase, the call to the function Intersect(p, T ) becomes more and more computationally expensive. It was observed in that when the input polynomial system is zero-dimensional and T is one-dimensional then this cost can be substantially reduced. The method proposed by the authors is a probabilistic algorithm based on evaluation and interpolation techniques. This is the type of method which is typically challenging to implement in a high-level language like Maple’s language, as a sharp control of computing resources (in particular memory) is needed. In this document, we report on a successful implementation of this algorithm in Maple as well as in the BPAS library.

On the other hand, multivariate Laurent series are a generalization of multivariate power series. They play an important roll when defining Puiseux series, and in consequence, they are required to implement Nowak’s version of the famous Newton-Puiseux algorithm. In this document, we also report a first implementation of a Laurent series object inside Maple together with the challenges that we have encountered during its development.