EN
We introduce and study a class of random walks defined on the integer lattice $ℤ^{d}$-a discrete space and time counterpart of the symmetric α-stable process in $ℝ^{d}$. When 0 < α <2 any coordinate axis in $ℤ^{d}$, d ≥ 3, is a non-massive set whereas any cone is massive. We provide a necessary and sufficient condition for a thorn to be a massive set.