Using the Gauss-Bonnet theorem, Stephen Hawking proved that the topology of the event horizon of a (four dimensional) black hole is a 2-sphere.
使用高斯-博内定理， 史蒂芬· 霍金证明一个（四维）黑洞活动视界的拓扑结构是2个球体。
2
Gausstheorem in magnetic field and Ampere cycle theorem, Ampere law, action of magnetic field to current line, cycle and charge in which.
磁场中的高斯定理和安培环路定理；安培定律。磁场对载流导线和载流线圈及对运动电荷的作用。
3
Based on the ampere return circuit theorem, gausstheorem and charge conservation law the concrete form of displacement current is derived. The displacement current is discussed.