Geometry of Quadrics and Spectral Theory
Geometry of Quadrics and Spectral Theory
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DOI:
10.1007/978-1-4613-8109-9_7
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发表时间:
1980
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影响因子:
--
通讯作者:
J. Moser
中科院分区:
文献类型:
--
作者:
J. Moser
In this paper we are concerned with integrable Hamiltonian systems. This concept goes back to classical analytical dynamics of the last century. Briefly these are nonlinear systems of ordinary differential equations described by a Hamiltonian function and possessing sufficiently many integrals (or conserved quantities) so that they are more or less explicitly solvable by quadrature. Therefore these systems played a crucial role in the last century before more qualitative methods for differential equations were developed at the turn of the century. Subsequently interest in these systems decreased, partly due to the realization that the existence of global integrals can be established only for exceptional Hamiltonian systems.In the last 15 years the subject of integrable Hamiltonian system has regained considerable interest with the discovery of some partial differential equations which can be viewed as such systems with infinite degrees of freedom. In this case the integrals form an infinite sequence of conserved functionals. The most celebrated example is the Korteweg-deVries equation: ut+ uUx+ uxxx= O. Extensive investigations of this equation have led to surprising links with scattering theory, spectral theory, complex analysis of hyperelliptic curves and their 0-functions, and differential geometry.