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A Darboux-Getzler theorem for scalar difference Hamiltonian operators

Casati, Matteo, Wang, Jing Ping (2020) A Darboux-Getzler theorem for scalar difference Hamiltonian operators. Communications in Mathematical Physics, 374 . pp. 1497-1529. ISSN 0010-3616. E-ISSN 1432-0916. (doi:10.1007/s00220-019-03497-2) (KAR id:73755)

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In this paper we extend the notion of Poisson–Lichnerowicz cohomology, an object encapsulating the building blocks for the theory of deformations of Hamiltonian operators, to the difference case. A local scalar difference Hamiltonian operator is a polynomial in the shift operator and its inverse, with coefficients in the algebra of difference functions, endowing the space of local functionals with the structure of a Lie algebra. Its Poisson–Lichnerowicz cohomology carries information about the center, the symmetries and the admissible deformations of such an algebra. The analogue notion for the differential case has been widely investigated: the first and most important result is the triviality of all but the lowest cohomology for first order Hamiltonian differential operators, due to Getzler. We study the Poisson–Lichnerowicz cohomology for the operator \(K_0=S−S^{−1}\), which is the normal form for (−1,1) order scalar difference Hamiltonian operators; we obtain the same result as Getzler did, namely \(H^p(K_0)=0∀p>1\), and explicitly compute \(H^0(K_0)\) and \(H^1(K_0)\). We then apply our main result to the classification of lower order scalar Hamiltonian operators recently obtained by De Sole, Kac, Valeri, and Wakimoto.

Item Type: Article
DOI/Identification number: 10.1007/s00220-019-03497-2
Subjects: Q Science > QA Mathematics (inc Computing science)
Q Science > QC Physics > QC20 Mathematical Physics
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Mathematics, Statistics and Actuarial Science
Funders: Engineering and Physical Sciences Research Council (
Depositing User: Matteo Casati
Date Deposited: 27 Jun 2019 15:11 UTC
Last Modified: 04 Mar 2024 18:51 UTC
Resource URI: (The current URI for this page, for reference purposes)

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