DefinitionGreen's Theorem - Green's Theorem is a fundamental theorem in vector calculus that relates the line integral of a vector field over a simple closed curve to the flux of the vector field through the enclosed region. It relates the circulation around a curve to the flux through a region, allowing a complicated line integral to be turned into a more easily-computable area integral. Green's theorem has applications in the study of fluid flow, electromagnetism and conservative field in physics, engineering, and mathematics. Greens Theorem: If F=(P,Q) is a vector field and C is a postively oriented simple closed curve that encloses the region D then ∮C(Pdx+Qdy)=∬D(∂x∂Q−∂y∂P)dA