We consider the following perturbed critical Dirichlet problem involving the
Hardy–Schrödinger operator:
when
is small,
,
and where
,
, is a smooth bounded
domain with
. We show that
there exists a sequence
in
with
such that,
if
for
any and
, then the above
equation has for
small,
a positive — in general nonminimizing — solution that develops a bubble at the origin. If moreover
, then for any integer
, the equation has
for small enough
a sign-changing solution that develops into a superposition of
bubbles with alternating sign centered at the origin. The
above result is optimal in the radial case, where the condition
is not necessary. Indeed,
it is known that, if
and
is a ball
, then there is no radial
positive solution for
small. We complete the picture here by showing that, if
,
then the above problem has no radial sign-changing solutions for
small.
These results recover and improve what is already known in the nonsingular case, i.e.,
when
.
Keywords
critical problem, Hardy potential, linear perturbation,
blow-up point