Long exact sequence of homotopy groups of a fibration (source code)

= Long exact sequence of homotopy groups of a fibration

For a based fibration $F\to E\to B$, lifting representatives defines connecting maps and an exact sequence
$$
\cdots\to\pi_k(F)\to\pi_k(E)\to\pi_k(B)
\xrightarrow{\partial}\pi_{k-1}(F)\to\cdots.
$$