Nonlocal brackets and integrable string models

Abstract

The closed string model in the background gravity field is considered as the bi-Hamiltonian system in assumption that string model is the integrable model for particular kind of the background fields. The dual nonlocal Poisson brackets, de pending of the background fields and of there derivatives, are obtained. The integrability condition is formulated as compatibility of the bi-Hamiltonity con dition and the Jacobi identity of the dual Poisson bracket. Two types of the non local brackets are introduced. Constant curvature and time-dependent metrics are considered, as example. It is, shown that the Jacobi identities for the non local brackets have particular solution for the space-time coordinates, as matrix representation of the simple Lie group.