Algebraic Topology: Homotopy and Homology
《Algebraic Topology: Homotopy and Homology》 · 第 133 页 · Definition 8.1
A spectrum \(E\) is a collection of pointed CW complexes \(E_n\) such that \(\Sigma E_n\) is a subcomplex of \(E_{n+1}\) for every \(n\in\mathbb Z\).