An algorithmic characterization
An algorithmic characterization
复制标题
算法表征
DOI:
--
复制
发表时间:
2007
期刊:
影响因子:
--
通讯作者:
Y. Lequain
中科院分区:
文献类型:
--
作者:
Y. Lequain
Let K be a field of characteristic zero, d a derivation of K [X; Y1, . . . , Yn] of the type d = ∂X + ∑n i=1(ai Yi + bi )∂Yi with ai , bi ∈ K [X ] for every i . We characterize the property “d is a simple derivation of K [X; Y1, . . . , Yn]” in terms of a certain property of d, a property that one can effectively check for whether it is satisfied or not. We apply our algorithm to exhibit families of simple derivations of K [X; Y1, . . . , Yn] that are very different from what has been known until now. We also show that our algorithm can be traduced into one that determines effectively whether the solutions in the power series ring K [[t]] of the system of algebraic equations { y i (t) = ai (t + α)yi (t) + bi (t + α) }n i=1 , α ∈ K , are algebraically independent over K (t) or not. c © 2007 Elsevier B.V. All rights reserved. MSC: Primary: 13.N.15; secondary: 13.P.99