| Popis: |
A spacetime symmetry group is any group which may be used as the structure group for the tangent bundle to spacetime. I list many such groups and the corresponding principal bundles. The most familiar are: the Lorentz group = 0(3,1,8) which uses the bundle of orthonormal frames, GL(4,R) with the general linear frame bundle, the Poincare group = IO(3,1,R) with the affine orthonormal frame bundle, and the spinor group, SL(2,C), with the orthonormal spinor frame bundle. The group GL(2,C) is also interesting because it leads to a unification of electromagnetism with a Weyl-Cartan theory of gravity. |
