“Gravity is that field which corresponds to a gauge invariance with
respect to displacement transformations.” Richard Feynman[i]

[i] http:/arXiv.org/abs/gr-qc/9602013 F. Hehl, p. 21


There is a part of F. Hehl's paper 1996 that to me suggests a
connection of the torsion gap, i.e. dislocation density in Kleinert's
world crystal lattice as a kind of poor-man's noncommutative geometry
i.e. 4.3 eqs 51 - 53

More on this - also supersymmetry is the square root of T4 and
Feynman means T4 above - same as me. Same as Hehl. Of course to do it
right we need full 10 parameter Poincare group. T4 enough to get
Einstein 1915 GR with non-dynamical "dummy" spin connections like the
Wheeler-Feynman EM potentials eliminated in terms of the charges &
action both ways in time on the light cones.

Hehl cites a Phys Rev. D Editor high energy theorist Lowell S. Brown who does not
understand Noether's theorem nor what Feynman says above and has
banned torsion papers from Phys. Rev like Stapp's paper on
retrocausality caused a similar ban on related papers!