The Pfaff lattice on symplectic matrices

dc.creatorKodama, Yuji
dc.creatorPierce, Virgil U.
dc.date2008-02-15
dc.date2009-05-27
dc.date.accessioned2026-07-07T13:18:00Z
dc.date.available2026-07-07T13:18:00Z
dc.descriptionThe Pfaff lattice is an integrable system arising from the SR-group factorization in an analogous way to how the Toda lattice arises from the QR-group factorization. In our recent paper [{\it Intern. Math. Res. Notices}, (2007) rnm120], we studied the Pfaff lattice hierarchy for the case where the Lax matrix is defined to be a lower Hessenberg matrix. In this paper we deal with the case of a symplectic lower Hessenberg Lax matrix, this forces the Lax matrix to take a tridiagonal shape. We then show that the odd members of the Pfaff lattice hierarchy are trivial, while the even members are equivalent to the indefinite Toda lattice hierarchy defined in [Y. Kodama and J. Ye, {\it Physica D}, {\bf 91} (1996) 321-339]. This is analogous to the case of the Toda lattice hierarchy in the relation to the Kac-van Moerbeke system. In the case with initial matrix having only real or imaginary eigenvalues, the fixed points of the even flows are given by $2\times 2$ block diagonal matrices with zero diagonals. We also consider a family of skew-orthogonal polynomials with symplectic recursion relation related to the Pfaff lattice, and find that they are succinctly expressed in terms of orthogonal polynomials appearing in the indefinite Toda lattice.
dc.identifierhttps://arxiv.org/abs/0802.2288
dc.identifierhttp://arxiv.org/abs/0802.2288
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/231298
dc.subjectExactly Solvable and Integrable Systems
dc.subjectMathematical Physics
dc.subjectOptimization and Control
dc.titleThe Pfaff lattice on symplectic matrices
dc.typetext

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