News for hackers. Stuff that matters.

A comment on Who Did the Math for General Relativity First, Einstein or Hilbert?. Parent comment

Re:Who Did the Math for General Relativity First, Einstein o... by throw0101a on Wednesday August 07, 2019 @11:55AM (#20635861)
> In fact a student of Lorentz, Fokker, working with Einstein was able to show that Nordstrom's theory was equivalent to an expression involving the ricci scalar and a trace of the stress energy tensor. Unlike Einstein's proposal around this time, it was diffeomorphism invariant.

"I know some of these words."

[ Parent | on HN ]
Re:Who Did the Math for General Relativity First, Einstein o... by danharaj on Wednesday August 07, 2019 @12:04PM (#20635945)
Ricci scalar: number assigned to each point of a space describing curvature at that point

Stress-energy tensor (field): multidimensional quantity assigned to each point of a space describing how matter and energy are concentrated and moving at that point.

Trace: coordinate invariant transformation that turns a tensor field into a scalar field.

Diffeomorphism invariant: the object in question has the same description regardless of arbitrary coordinate changes

[ Parent | on HN ]