Algebraic Topology
《Algebraic Topology》 · 第 407 页 · Section 4.3
The homotopy fiber \(F_f\) of \(f:A\to B\) consists of all pairs \((a,\gamma)\) with \(a\in A\) and \(\gamma\) a path in \(B\) from \(f(a)\) to a basepoint \(b_0\).