Finding an Antiderivative for an Exact Form
Clash Royale CLAN TAG #URR8PPP up vote 0 down vote favorite Let $omega$ be an exact $1$-form on a path-connected manifold $M$. For a fixed $x in M$ we can define for all $y in M$. $$ g(y) := int_gamma gamma^*(omega), $$ where $gamma$ is a path from $x$ to $y$. Because $omega$ is exact, it is independent of $gamma$. What I want to show is that $dg = omega$. My thought is that $$ dleft( int_gamma gamma^*(omega) right) = int d(omega(gamma)), $$ because $d$ commutes with integration, and $gamma^*(omega)$ is defined to be $omega(gamma(t))$. Then $$ d(omega(gamma)) = domega(gamma) cdot dgamma $$ by chain rule. By change of variable, we get $$ int d omega = omega. $$ But, someone pointed out that $domega = 0$ by exactness. My thought is that this is only true when integrating over closed paths. What's going on? Thanks. Edit: Another thought is that $d(omega)$ and $domega$ are two different things. So, that $d(omega) = 0$, but $domega$ is a element of the cotangent bundle. Thu