Changes

where we use the metric signature (+,+,+,-) and<br>

where we use the metric signature (+,+,+,-) and<br>

:<math>A^\mu = (\mathbf{A},\frac{\Phi} {c})</math>

:<math>A^\mu = (\mathbf{A},\frac{\Phi} {c})</math>

:<math>\square^2=\part_\mu \part^\mu = \nabla^2 - \frac{1}{c^2} \frac{\part^2}{\part t^2}</math><br><br>

:<math>\square^2=\part_\mu \part^\mu = \nabla^2 - \frac{1}{c^2} \frac{\part^2}{\part t^2}</math><br>

:<math>j^\mu = (\mathbf{j},c\rho), \part_\mu= (\mathbf{\nabla}, \frac{1}{c} \frac{\part}{\part t})</math><br>

:<math>j^\mu = (\mathbf{j},c\rho), \part_\mu= (\mathbf{\nabla}, \frac{1}{c} \frac{\part}{\part t})</math><br>

The gauge condition for the Lorentz gauge is

The gauge condition for the Lorentz gauge is