One more question before Santa comes. There are a number of different related threads, so hopefully I'm not repeating this - however, I haven't found a crisp answer yet. If one introduces a UV cutoff in the vacuum energy (in an attempt to avoid having infinite vacuum energy), is it possible at all to preserve Lorentz invariance? I thought at one time I'd read an abstract about this, but can't find it now. In Minkowski spacetime, any UV cutoff would lead to Lorentz violation, correct? Since there are strong constraints on Lorentz invariance violation from, e.g., astrophysical data (Fermi, etc.), do we have to look to new physics (quantum gravity) for a solution to this problem?