Ga-actions of fiber type on affine T-varieties

JOURNAL OF ALGEBRA

卷:324

Article

Liendo, Alvaro

关键词: Torus action;    G(a) action;    Locally nilpotent derivations;    Affine varieties;    Makar Limanov invariant;   

DOI  :  10.1016/j.jalgebra.2010.09.008

来源: Elsevier

【 摘 要 】

Let X be a normal affine T-variety where T stands for the algebraic torus We classify G(a)-actions on X arising from homogeneous locally nilpotent derivations of fiber type We deduce that any variety with trivial Makar-Limanov (ML) invariant is birationally decomposable as Y x P-2 for some Y Conversely given a variety Y there exists an affine variety X with trivial ML invariant birational to Y x P-2 Finally we introduce a new version of the ML invariant called the FML invariant According to our conjecture the triviality of the FML invariant implies rationality We confirm this conjecture in dimension at most 3 (C) 2010 Elsevier Inc All rights reserved

【 授权许可】

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