  Majumdar and Tamm [Phys. Rev. E 86 021135 (2012), arXiv:1206.6184] recently
obtained analytical expressions for the mean number of common sites W_N(t)
visited up to time t by N independent random walkers starting from the origin
of a d-dimensional lattice. In this short note I show how the different regimes
and the corresponding asymptotic power laws can be retrieved using the notion
of fractal intersection.
