We study the following parabolic problem
$u_t-$ div $(|x|^{-p\gamma}|\nabla u|^{p-2}\nabla
u) = \lambda f(x,u), u\ge 0$ in $\Omega\times (0,T)$,
$ B(u) = 0$ on $\partial\Omega\times (0,T),$
$ u(x,0) = \varphi (x)\quad$ if $x\in\Omega$,
where $\Omega\subset\mathbb R^N$ is a smooth bounded domain with $0\in\Omega$,
$B(u)\equiv u\chi_{\Sigma_1\times(0,T)}+|x|^{-p\gamma}
|\nabla u|^{p-2}\frac{\partial u}{\partial
\nu}\chi_{\Sigma_2 \times (0,T)}$
and
$-\infty<\gamma<\frac{N-p}{p}$. The boundary conditions over
$\partial\Omega\times (0,T)$ verify hypotheses that will be precised in each case.
Mainly, we will consider the second member
$f(x,u)=\frac{u^{\alpha}}{|x|^{p(\gamma+1)}}$ with $ \alpha\ge p-1$, as a model case. The
main points under analysis are some existence, nonexistence and
complete blow-up results related to some Hardy-Sobolev
inequalities and a weak version of Harnack inequality, that holds
for $p\ge 2$ and $\gamma+1>0$.
{{journal.titleEn}} 
DownLoad: