Mayer–Vietoris property for relative symplectic cohomology

In this paper, we construct a Hamiltonian Floer theory based invariant called relative symplectic cohomology, which assigns module over the Novikov ring to compact subsets of closed manifolds. We show existence restriction maps, and prove some basic properties. Our main contribution is identify natural geometric situation in cohomology two satisfy Mayer-Vietoris property. This tailored work under certain integrability assumptions, weakest introduces new object barrier - roughly, one parameter family rank 2 coisotropic submanifolds. The proof uses deformation argument topological energy zero (i.e. constant) solutions are actors.