I'm just learning about differential forms and I've noticed something in my homework assignment. We have to evaluate zdx + xdy + ydz, over directed line segments in R-three by the method of pullback. Let a, b, and c be vectors in R-three. I noticed that Integral from a to c does NOT equal integral from a to b + integral from b to c, as it does with normal integrals. I think that this would make sense, since the meaning of zdx +xdy +ydz, which you are integrating, depends on the line segment in question. Is it true that this rule does not apply with these kinds of integrals, or have I simply made a mistake somewhere in my calculations? Thanks.