arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.05271math.RTmath.AGmath.SG
收藏

与2-分裂相关的相容泊松括号和$\mathcal S(\mathfrak g)$的Poisson交换子代数

Compatible Poisson brackets associated with 2-splittings and Poisson commutative subalgebras of $\mathcal S(\mathfrak g)$

Dmitri Panyushev, Oksana Yakimova

摘要:

设${\mathcal S}(\mathfrak g)$是具有标准Poisson结构的约化李代数$\mathfrak g$的对称代数。若${\mathcal C}\subset\mathcal S(\mathfrak g)$是Poisson-交换子代数,则有${\rm trdeg\,}{\mathcal C}\le\boldsymbol{b}(\mathfrak g)$,其中$\boldsymbol{b}(\mathfrak g)=(\dim\mathfrak g+{\rm rk}\mathfrak g)/2$ .给出了一种构造超越度为$\boldsymbol{b}(\mathfrak g)$的Poisson-交换子代数$\mathcal Z_{\langle\mathfrak h,\mathfrak r\rangle}$的方法,通过将$\mathfrak g=\mathfrak h\oplus\mathfrak r$分解为两个球面子代数之和。有一些自然的例子,其中代数$\mathcal Z_{\langle\mathfrak h,\mathfrak r\rangle}$似乎是多项式。最有趣的情况是与对$(\mathfrak b,\mathfrak u_-)$有关,其中$\mathfrak b$是$\mathfrak g$的Borel子代数。本文证明了${\mathcal Z}_{\langle\mathbb b,\mathbb u_-\rangle}$是极大Poisson-可换的,并且在$\mathfrak g^*$的每一个正则余伴轨道上都是完备的.其他一系列的例子与$\mathfrak g$的对合相关的分解有关。

英文摘要:

Let ${\mathcal S}(\mathfrak g)$ be the symmetric algebra of a reductive Lie algebra $\mathfrak g$ equipped with the standard Poisson structure. If ${\mathcal C}\subset\mathcal S(\mathfrak g)$ is a Poisson-commutative subalgebra, then ${\rm trdeg\,}{\mathcal C}\le\boldsymbol{b}(\mathfrak g)$, where $\boldsymbol{b}(\mathfrak g)=(\dim\mathfrak g+{\rm rk}\mathfrak g)/2$. We present a method for constructing the Poisson-commutative subalgebra $\mathcal Z_{\langle\mathfrak h,\mathfrak r\rangle}$ of transcendence degree $\boldsymbol{b}(\mathfrak g)$ via a vector space decomposition $\mathfrak g=\mathfrak h\oplus\mathfrak r$ into a sum of two spherical subalgebras. There are some natural examples, where the algebra $\mathcal Z_{\langle\mathfrak h,\mathfrak r\rangle}$ appears to be polynomial. The most interesting case is related to the pair $(\mathfrak b,\mathfrak u_-)$, where $\mathfrak b$ is a Borel subalgebra of $\mathfrak g$. Here we prove that ${\mathcal Z}_{\langle\mathbb b,\mathbb u_-\rangle}$ is maximal Poisson-commutative and is complete on every regular coadjoint orbit in $\mathfrak g^*$. Other series of examples are related to decompositions associated with involutions of $\mathfrak g$.

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。

↑