Solution
= Solution
The <Weinstein neighborhood theorem> states that if $L$ is a compact <Lagrangian submanifold> of $(M,\omega)$, then neighborhoods of $L$ in $M$ and of the zero section in its <cotangent bundle> $T^*L$ are <symplectomorphic>. The symplectomorphism restricts to the identity on $L$, and the canonical form on $T^*L$ is taken with the sign matching the chosen convention.