University of Oxford
Hamiltonian and quasi-Hamiltonian reduction via derived symplectic geometry
I will explain an approach to Hamiltonian reduction using derived symplectic geometry. Roughly speaking, the reduced space can be presented as an intersection of two Lagrangians in a shifted symplectic space, which therefore carries a natural symplectic structure. A slight modification of
the construction gives rise to quasi-Hamiltonian reduction. In the end I will mention how quasi-Hamiltonian reduction naturally fits into a classical topological field theory called classical Chern–Simons theory.