(2+2)-dimensional flat spacetime with neutral signature
32625
More than one time dimension
123235
A smooth vector field on $S^2$ vanishing at a single point
79861
Induced metric on a null hypersurface
152766
3-dim simple complex Lie algebra
57097
Massless particle in FRW metric
145003
How can a point-like particle "feel" gravity, if locally the curvature of spacetime is always flat?
23729
Four-velocity in General-relativistic geodesic equation
151086
What bends fabric of space-time?
70257
Inverse metric in linearised gravity
60787
Natural density of solvable quintics
36152
Bessel function representation of spacelike KG propagator
63402
Euler-Lagrange equation in curved spacetime: how to calculate $\partial \mathcal{L}/\partial(\nabla_\nu A_\mu)$?
60751
General relativity and the conservation of momentum
45802
Spacetime Torsion, the Spin tensor, and intrinsic spin in Einstein-Cartan theory
56911
Proving invariance of $ds^2$ from the invariance of the speed of light
101418
Can we define flat connection on any given smooth manifold?
10209
How to show the spacetime interval is invariant in general?