RT info:eu-repo/semantics/article T1 A first approach towards normal parametrizations of algebraic surfaces A1 Pérez Díaz, Sonia A1 Sendra Pons, Juan Rafael A1 Villarino Cabellos, Carlos K1 Rational surface K1 Normal parametrizations K1 Surjectivity K1 Normality of a rational parametrization K1 Pseudo-normal parametrization K1 Matemáticas K1 Mathematics AB In this paper we analyze the problem of deciding the normality (i.e. thesurjectivity) of a rational parametrization of a surface S. The problem canbe approached by means of elimination theory techniques, providing a properclose subset Z ⊂ S where surjectivity needs to be analyzed. In general, thesedirect approaches are unfeasible because Z is very complicated and its elements computationally hard to manipulate. Motivated by this fact, we studyad hoc computational alternative methods that simplifies Z. For this goal,we introduce the notion of pseudo-normality, a concept that provides necessary conditions for a parametrization for being normal. Also, we provide analgorithm for deciding the pseudo-normality. Finally, we state necessary andsufficient conditions on a pseudo-normal parametrization to be normal. As aconsequence, certain types of parametrizations are shown to be always normal. For instance, pseudo-normal polynomial parametrizations are normal.Moreover, for certain class of parametrizations, we derive an algorithm fordeciding the normality. PB World Scientific SN 0218-1967 YR 2010 FD 2010-12 LK http://hdl.handle.net/10017/49610 UL http://hdl.handle.net/10017/49610 LA eng NO Ministerio de Ciencia e Innovación DS MINDS@UW RD 25-abr-2024