Mountain Math Software, P. O. Box 2124, Saratoga. It may seem unlikely that space-time is a lattice It contradicts fundamental assumptions in physics.
Special relativity can only be approximately true.
There must be absolute preferred directions. One might think the experimental evidence against this possibility is overwhelming. This is obviously false. We can use a lattice to approximate a continuous model with arbitrarily accuracy by choosing the grid of the lattice sufficiently small. If space-time is a lattice its dimensions are likely to be on the order of the Plank time and distance scales.