Using the Maxwell equations, one can see that the electromagnetic stress–energy tensor (defined above) satisfies the following differential equation, relating it to the electromagnetic tensor and the current four-vector T α α β β , β β + F α α β β J β β = 0 or η η α α ν ν T ν ν β β , β β + F α α β β J β β = 0 , which expresses the conservation of linear momentum and energy by electromagnetic interactions.