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arXiv 2409.09017math.RA
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幂零李代数上的不变度量

Invariant Metrics on Nilpotent Lie algebras

R. García-Delgado

AI总结:

本研究给出幂零李代数容许不变度量的判别准则与充分条件,证明了当前李代数容许不变度量的必要条件,以及任意幂零李代数存在非零对称不变双线性型且其对应含单位元代数为单代数的充要条件。

摘要:

我们给出了幂零李代数$\frak{g}$容许不变度量的判别准则。利用$\frak{g}$具有两个典范交换理想$\frak{ide}(\frak{g}) \subset \mathfrak{J}(\frak{g})$这一性质,我们对$\frak{g}$的底向量空间进行分解,进而给出$\frak{g}$容许不变度量的充分条件。借助理想$\mathfrak{J}(\frak{g})$的性质,我们证明:若当前李代数$\frak{g} \otimes \Sa$容许不变度量,则必然存在一个从$\Sa \times \Sa$到$\frak{g}/\mathfrak{J}(\frak{g})$的形心空间的不变非退化双线性映射。我们还证明,任意幂零李代数$\frak{g}$中都存在非零的对称不变双线性型。该双线性型可通过含单位元的代数重构$\frak{g}$,且我们证明该代数是单代数当且仅当此双线性型是$\frak{g}$上的不变度量。

英文摘要:

We state criteria for a nilpotent Lie algebra $\g$ to admit an invariant metric. We use that $\g$ possesses two canonical abelian ideals $\ide(\g) \subset \mathfrak{J}(\g)$ to decompose the underlying vector space of $\g$ and then we state sufficient conditions for $\g$ to admit an invariant metric. The properties of the ideal $\mathfrak{J}(\g)$ allows to prove that if a current Lie algebra $\g \otimes \Sa$ admits an invariant metric, then there must be an invariant and non-degenerate bilinear map from $\Sa \times \Sa$ into the space of centroids of $\g/\mathfrak{J}(\g)$. We also prove that in any nilpotent Lie algebra $\g$ there exists a non-zero, symmetric and invariant bilinear form. This bilinear form allows to reconstruct $\g$ by means of an algebra with unit. We prove that this algebra is simple if and only if the bilinear form is an invariant metric on $\g$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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