4 papers
An Effective Criterion for Covering Maps Between Real Varieties
Rizeng Chen
We prove that a quasi-finite flat morphism with locally constant geometric-fiber cardinality between varieties over a real closed field induces a covering map on the rational point…
Stratifying Discriminant Hypersurface
Rizeng Chen, Hoon Hong, Jing Yang
This paper investigates the stratification of the discriminant hypersurface associated with a univariate polynomial via the number of its distinct complex roots. We introduce two n…
A Geometric Approach to Cylindrical Algebraic Decomposition
Rizeng Chen
Cylindrical algebraic decomposition is a classical construction in real algebraic geometry. Although there are many algorithms to compute a cylindrical algebraic decomposition, the…
What Kind of Morphisms Induces Covering Maps over a Real Closed Field?
Rizeng Chen
In this article, we show that a flat morphism of -varieties () with locally constant geometric fibers becomes finite étale after reduction. When …