Thread: theory of relativity

What is the minimum definition of the theory of relativity? Like how short can one make a meaningful and relatively complete definition of the theory of relativity?

how short - I would vote for :the covariant divergence of the energy-momentum tensor is zero.
or just the equation
G =8 pi T

Aside from the fact that relativity is not a complete theory, the best definition is one that states the principle hypotheses. The rest is just math.

Relativity = Light is maximum possible velocity + speed of light in vacuum is same in all reference frames + laws of physics are independent of reference frame + equivalence principle (gravity and acceleration are indiscernible WRT distant objects in universe).

Dennis C's equation is true of infinitely many manifolds, whether they describe our universe or not.