  We study the isolated singularities of functions satisfying (E) (--$\Delta$)
s v$\pm$|v| p--1 v = 0 in $\Omega$\{0}, v = 0 in R N \$\Omega$, where 0 < s <
1, p > 1 and $\Omega$ is a bounded domain containing the origin. We use the
Caffarelli-Silvestre extension to R + x R N. We emphasize the obtention of a
priori estimates, analyse the set of self-similar solutions via energy methods
to characterize the singularities.
