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This article is cited in 8 scientific papers (total in 8 papers)
Birational Darboux Coordinates on (Co)Adjoint Orbits of $\operatorname{GL}(N,\mathbb C)$
M. V. Babich St. Petersburg Department of Steklov Mathematical Institute of Russian Academy of Sciences
Abstract:
The set of all linear transformations with a fixed Jordan structure $\mathcal J$ is a symplectic manifold isomorphic to the coadjoint orbit $\mathcal O (\mathcal J)$ of the general linear group $\operatorname{GL}(N,{\mathbb C})$. Any linear transformation can be projected along its eigenspace onto a coordinate subspace of complementary dimension. The Jordan structure $\tilde{\mathcal J}$ of the image under the projection is determined by the Jordan structure $\mathcal J$ of the preimage; consequently, the projection
$\mathcal O (\mathcal J)\to \mathcal O (\tilde{\mathcal J})$ is a mapping of symplectic manifolds.
It is proved that the fiber $\mathscr{E}$ of the projection is a linear symplectic space and the map $\mathcal O(\mathcal J) \stackrel{\sim}{\to} \mathscr{E} \times \mathcal O (\tilde{\mathcal J})$ is a birational symplectomorphism. Successively projecting the resulting transformations along eigensubspaces yields an isomorphism between $\mathcal O (\mathcal J)$ and the linear symplectic space being the direct product of all fibers of the projections. The Darboux coordinates on $\mathcal O(\mathcal J)$ are pullbacks of the canonical
coordinates on this linear symplectic space.
Canonical coordinates on orbits corresponding to various Jordan structures are constructed as examples.
Keywords:
Jordan normal form, Lie–Poisson–Kirillov–Kostant form, birational symplectic coordinates.
Received: 22.09.2014
Citation:
M. V. Babich, “Birational Darboux Coordinates on (Co)Adjoint Orbits of $\operatorname{GL}(N,\mathbb C)$”, Funktsional. Anal. i Prilozhen., 50:1 (2016), 20–37; Funct. Anal. Appl., 50:1 (2016), 17–30
Linking options:
https://www.mathnet.ru/eng/faa3222https://doi.org/10.4213/faa3222 https://www.mathnet.ru/eng/faa/v50/i1/p20
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Abstract page: | 417 | Full-text PDF : | 171 | References: | 83 | First page: | 57 |
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