The momentum section theory is a generalization of the momentum map theory in symplectic manifolds with a Lie group action to Lie groupoid setting. We show that a simple Hamiltonian mechanics with constraint conditions naturally has a momentum section structure. Moreover, in order to apply the theory to nonlinear sigma models, we propose a generalization of the momentum section to multisymplectic manifolds. This talk is based on joint works with Thomas Strobl and Yuji Hirota.
Thomas Strobl