∇⋅B=0 \nabla \cdot \mathbf{B} = 0 ∇⋅B=0
∇×E=−∂B∂t \nabla \times \mathbf{E} = - \frac{\partial \mathbf{B}}{\partial t} ∇×E=−∂t∂B
∇×B=1c2∂E∂t \nabla \times \mathbf{B} = \frac{1}{c^2} \frac{\partial \mathbf{E}}{\partial t} ∇×B=c21∂t∂E