About 4.0
The Four Point Zero project aims to produce the next generation of relativity theory.
The reason for the numbering is straightforward:
Einstein's special theory of relativity was Relativity mk2
Einstein's general theory of relativity was Relativity mk3
and this ... is Relativity 4.0
Four Point Zero is a reinvention of general relativity, a "GR mk2". It doesn't fit the existing GR1915-based definitions that are currently used to assess gravitational models, and it doesn't work with the current classification scheme for categorising variations on general relativity. Since it's not a simple incremental development of current GR research, and isn't compatible with the current standard definitions, it earns itself a "major revision number" increment.
Four Point Zero eliminates Einstein's special theory from the description. It's a "purist", total-rewrite, ground-up reimplementation of general relativity, in a truly general form, without any intermediate layers of theory based on other principles.
It converges with quantum mechanics in ways that current GR can't, it eliminates the scaling distinction between theories, applies the same principles to cosmology and particle physics, introduces a new set of restrictive equivalence principles, and aims to remove every single fudge, mudge and bodge from current relativity theory. It's a "clean-room" reinvention of the relativistic wheel, the way it should have been.
The transition to 4.0 involves some changes to current theory.
www.fourpointzero.org/4.0_about.html