As I understand, the lack of indication on how to obtain first integrals in Arnol'd-Liouville theory is a reason why we are interested in bi-Hamiltonian systems.
Two Poisson brackets
cdot,cdot1,cdot,cdot2 on a manifold M are compatible if their arbitrary linear combination
lambdacdot,cdot1+mucdot,cdot2 is also a Poisson bracket. A bi-Hamiltonian system is one which allows Hamiltonian formulations with respect to two compatible Poisson brackets. It automatically posseses a number of integrals in involution.
The definition of a complete integrability (à la Liouville-Arnol'd) is:
Hamiltonian flows and Poisson maps on a 2n-dimensional symplectic manifold left(M,cdot,cdotMright) with n (smooth real valued) functions F1,F2,dots,Fn such that: (i) they are functionally independent (i.e. the gradients nablaFk are linearly independent everywhere on M) and (ii) these functions are in involution (i.e. Fk,Fj=0) are called completely integrable.
Now, I would like to understand the connections between these two notions, and because I haven't studied the theory, any answer would be helpful. I find reading papers on these subjects too technical at the moment. Specific questions I have in mind are:
Does completely integrable system always allow for a bi-Hamiltonian structure? Is every bi-Hamiltonian system completely integrable? If not, what are examples (or places where to find examples) of systems that posses one property but not the other?
I apologize for any stupid mistakes I might have made above. Feel free to edit (tagging included).
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