I'm looking at prop 19.5 of Taylor's PDE book.
The theorem is:
If M is a compact, connected, oriented manifold of dimension n, and a is an n-form, then a=dB where B is an n-1 form iff the ∫a over M is 0.
I'm trying to understand why a=dB implies ∫a = 0.
If M has no boundary, than this...