Maxwell's Equations

\begin{align} \nabla \times \vec{\mathbf{B}}-\, \frac1c\, \frac{ \partial\vec{\mathbf{E}}}{\partial t} &= \frac{4 \pi}{c}\vec{\mathbf{j}}\\ \nabla \cdot \vec{\mathbf{E}} &=4 \pi \rho \\ \nabla \times \vec{\mathbf{E}} \, + \, \frac1c \, \frac{\partial\vec{\mathbf{B}}}{\partial t} &= \vec{\mathbf{0}} \\ \nabla \cdot \vec{\mathbf{B}} &=0 \end{align}