Algebraic Topology: Homotopy and Homology
《Algebraic Topology: Homotopy and Homology》 · 第 365 页 · Theorem 15.46
If \(X\) is \(n\)-connected with \(n\ge1\), the suspension \(E:\pi_p(X,x_0)\to\pi_{p+1}(\Sigma X,*)\) is an isomorphism for \(p\le2n\) and an epimorphism for \(p=2n+1\).