We establish a system of PDE, called open WDVV, that constrains the bulk-deformed superpotential and associated Gromov–Witten invariants Lagrangian submanifold $L \subset X$ with bounding chain. Simultaneously, we define quantum cohomology algebra $X$ relative to $L$ prove its associativity. also connection it is flat. A wall-crossing formula derived allows interchange point-like boundary const...