Algebraic Topology: Homotopy and Homology
《Algebraic Topology: Homotopy and Homology》 · 第 357 页 · Section 15
For an oriented spherical fibration, if \(u\in H^n(S^n;R)\) is a generator, then \(e=d_{n+1}u\in H^{n+1}(B;R)\) is called its Euler class.