First,we we recall that symplectic manifold is a smooth manifold, M$M$, equipped with a closed nondegenerate differential 2-form, $\omega$, called the symplectic form. The study of symplectic manifolds is called symplectic geometry.In h$\ddot{o}$rmander's In Hörmander's classic book ALPDO (The analysis of partial differential operatorsⅠoperators Ⅰ-Ⅳ ),he wroted:symplectic he wrote: symplectic geometry pervades a large part of the modern theory of linear partial differential operators with variable coefficients.And And he had devoted the entire chapter ⅩⅩⅠtoⅩⅩⅠ to discuss it.
Now,with with some basic background ( itsits origins in the Hamiltonian formulation of classical mechanics) , I want to know further that why it would make such a important role in modern analysis (such as fourier integral operators) ?
Thanks in advance.