Thus far my professor showed us 3 ways to compute line integrals: Direct Potential (If curl F = 0) Homotopy Homotopic curve--- finding a curve q(t) that changes the path of integration, so that the L.I. can be computer much easier. My question MUST curl of any ForceField always have to be 0 for there to be a homotopy? What are some other restrictions? Thanks!