The weird thing is that there are two metrics involved: information can propagate through a nonempty universe at 1 cell per generation in the sense of the l_infinity metric, but it can only propagate into empty space at 1⁄2 a cell per generation in the sense of the l_1 metric.
The weird thing is that there are two metrics involved: information can propagate through a nonempty universe at 1 cell per generation in the sense of the l_infinity metric, but it can only propagate into empty space at 1⁄2 a cell per generation in the sense of the l_1 metric.
https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm