Title
Generalized polar varieties: geometry and algorithms
Abstract
Let V be a closed algebraic subvariety of the n-dimensional projective space over the complex or real numbers and suppose that V is non-empty and equidimensional. The classic notion of a polar variety of V associated with a given linear subvariety of the ambient space of V was generalized and motivated in Bank et al. (Kybernetika 40 (2004), to appear). As particular instances of this notion of a generalized polar variety one reobtains the classic one and an alternative type of a polar variety, called dual. As main result of the present paper we show that for a generic choice of their parameters the generalized polar varieties of V are empty or equidimensional and smooth in any regular point of V. In the case that the variety V is affine and smooth and has a complete intersection ideal of definition, we are able, for a generic parameter choice, to describe locally the generalized polar varieties of V by explicit equations. Finally, we indicate how this description may be used in order to design in the context of algorithmic elimination theory a highly efficient, probabilistic elimination procedure for the following task: In case, that the variety V is Q-definable and affine, having a complete intersection ideal of definition, and that the real trace of V is non-empty and smooth, find for each connected component of the real trace of V an algebraic sample point.
Year
DOI
Venue
2005
10.1016/j.jco.2004.10.001
J. Complexity
Keywords
DocType
Volume
Arithmetic network,real trace,14P05,Arithmetic circuit,14B05,68W30,algorithmic elimination theory,68Q25,polar variety,Geometric degree,variety V,real number,Generalized polar variety,Complexity,generalized polar variety,Real polynomial equation solving,ambient space,classic notion,Elimination procedure,Geometry of polar varieties and its generalizations,complete intersection ideal,algebraic sample point
Journal
21
Issue
ISSN
Citations 
4
Journal of Complexity
33
PageRank 
References 
Authors
1.21
21
4
Name
Order
Citations
PageRank
B. Bank1987.45
M. Giusti2542.46
J. Heintz316219.20
L. M. Pardo4726.82