A section of a vector fiber bundle \((E, \Pi, M)\) is a differentiable map \(\xi\colon M\to E\) with \(\Pi\circ \xi=\id\).
\[
\DeclareMathOperator{\id}{Id}
\]
A section of a vector fiber bundle \((E, \Pi, M)\) is a differentiable map \(\xi\colon M\to E\) with \(\Pi\circ \xi=\id\).