RISC-Linz RISC-Linz Research Institute for Symbolic Computation  

RISC Talk Announcement

Speaker: Prof. Rafael Sendra, Universidad de Alcala, Madrid, Spain
Title: Radical Varieties
Date: 19.07. 2018   10:15--11:30
Location: RISC Seminar room
Abstract: In many applications, where geometric constructions appear, parametrizations of the geometric objects are used. In practice, when the geometric entities are algebraic, the varieties are assumed to be rational, and hence representable by means of rational functions. This is a limitation of the feasibility of the application, since the class of rational varieties may turn to be small for the practical purposes. To overcome this difficulty one may use approximations or, alternatively, enlarge the family of functions allowed to be used in the parametric representation of the geometric object, for instance by introducing radicals of polynomials. This is the theoretical frame of this talk. In this talk, we will introduce the notion of rational parametrization as well as the associated concept of rational variety. Additionally, we will introduce a second, auxiliary, variety, named the tower variety. In addition, we will study some of their fundamental properties. From the computational point of view, we will present al- gorithms for implicitizing radical varieties and, for the particular cases of curves and surfaces, we will also present reparametrization and parametrization algorithms.
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