group $ K $ with respect to the standard Lie-Poisson structure. These systems generalize properties of Gelfand-Zeitlin systems for unitary and orthogonal Lie groups: 1) the pullback to any Hamiltonian $ K $-manifold is an integrable torus action, 2) if the $ K $-manifold is multiplicity free, then the torus action is\textit {completely} integrable, and 3) the collective moment map has convexity and fiber connectedness properties. They also generalize the …
We construct completely integrable torus actions on the dual Lie algebra of any compact Lie group with respect to the standard Lie-Poisson structure. These systems generalize properties of Gelfand-Zeitlin systems for unitary and orthogonal Lie groups: 1) the pullback to any Hamiltonian -manifold is an integrable torus action, 2) if the -manifold is multiplicity free, then the torus action is \textit{completely} integrable, and 3) the collective moment map has convexity and fiber connectedness properties. They also generalize the relationship between Gelfand-Zeitlin systems and canonical bases via geometric quantization by a real polarization. To construct these integrable systems, we generalize Harada and Kaveh's construction of integrable systems by toric degeneration to singular quasi-projective varieties. Under certain conditions, we show that the stratified-gradient Hamiltonian vector field of such a degeneration, which is defined piece-wise, has a flow whose limit exists and defines continuous degeneration map.