PERSON@1 's equations have a close relation to special relativity : Not only were PERSON@1 's equations a crucial part of the historical development of special relativity , but also , special relativity has motivated a compact mathematical formulation of PERSON@1 's equations , in terms of covariant tensors .

In special relativity , PERSON@1 's equations for the vacuum are written in terms of four-vectors and tensors in the `` manifestly covariant '' form .
