### 3.3 c-squared framework

The framework [277] is the flat space limit of the [205] framework. This framework
considers the motion of electromagnetically charged test particles in a spherically symmetric, static
gravitational field. are all parameters that fold in to the motion of the particles which vary
depending on the underlying gravitational model. In the flat space limit, which is the formalism, the
units are chosen such that limiting speed of the test particles is one while the speed of light is given in terms
of the parameters by . The and constructions can also be expressed
in terms on the standard model extension [179].