摘要翻译:
设G是作用于仿射簇X上的仿射代数群。在G是约化的情况下,我们给出了计算不变环K[X]^G生成元的一个算法。此外,我们还讨论了G是连通的且是单幂的情况,因此不变环不必有限生成。对于这种情况,我们提出了一个用所谓的冒号运算来计算K[X]^g的算法。由此,如果k[X]^g是有限生成的,则可以在有限时间内得到它的生成子。在K[X]为阶乘的附加假设下,我们给出了一个寻找坐标环为K[X]^g的拟仿射簇的算法。在此过程中,我们发展了一些处理非有限生成代数的技术。特别地,我们引入了有限生成轨迹理想。
---
英文标题:
《Computing invariants of algebraic group actions in arbitrary
characteristic》
---
作者:
Harm Derksen, Gregor Kemper
---
最新提交年份:
2007
---
分类信息:
一级分类:Mathematics 数学
二级分类:Commutative Algebra 交换代数
分类描述:Commutative rings, modules, ideals, homological algebra, computational aspects, invariant theory, connections to algebraic geometry and combinatorics
交换环,模,理想,同调代数,计算方面,不变理论,与代数几何和组合学的联系
--
一级分类:Mathematics 数学
二级分类:Algebraic Geometry 代数几何
分类描述:Algebraic varieties, stacks, sheaves, schemes, moduli spaces, complex geometry, quantum cohomology
代数簇,叠,束,格式,模空间,复几何,量子上同调
--
---
英文摘要:
Let G be an affine algebraic group acting on an affine variety X. We present an algorithm for computing generators of the invariant ring K[X]^G in the case where G is reductive. Furthermore, we address the case where G is connected and unipotent, so the invariant ring need not be finitely generated. For this case, we develop an algorithm which computes K[X]^G in terms of a so-called colon-operation. From this, generators of K[X]^G can be obtained in finite time if it is finitely generated. Under the additional hypothesis that K[X] is factorial, we present an algorithm that finds a quasi-affine variety whose coordinate ring is K[X]^G. Along the way, we develop some techniques for dealing with non-finitely generated algebras. In particular, we introduce the finite generation locus ideal.
---
PDF链接:
https://arxiv.org/pdf/0704.2594