In the theory of discrete Lorentzian quantum gravity, space itself is modeled by a lattice instead of a manifold.
This theory is different from other lattice methods, in that the geometry of the lattice is Minkowskian and not Euclidian in nature. The goal of this method was and is to come up with a variant of quantum gravity which would preserve Lorentz invariance without Wick rotation, which is questionable for pseudo Riemannian manifolds without a timelike Killing vector field.
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