Influence of an lp –perturbation on Hardy-Sobolev inequality with singularity a curve

We consider a bounded domain $\Omega~\text{of}~\mathbb{R}^{N}, N \geq 3, h \text{and} b$ continuous functions on $\Omega$. Let $Gamma$ be a closed curve contained in $\Omega$. We study existence of positive solutions $u \in H_{0}^{1}(\Omega)$ to the perturbed Hardy-Sobolev equation: $$-\Delta{}u + hu + bu^{1+\delta} = \rho_{\Gamma}^{-\sigma} u^{2_{\sigma}^{\star}-1}~\text{in}~\Omega,$$ where $2_{\sigma}^{\star} := \frac{2(N-\sigma)}{N-2}$ is the critical Hardy-Sobolev exponent $\sigma \in [0,2), 0 < \delta < \frac{4}{N-2}$ and $\rho_{\Gamma}$ is the distance function to $\Gamma$. We show that the existence of minimizers does not depend on the local geometry of $\Gamma$ nor on the potential $h$. For $N = 3$, the existence of ground-state solution may depends on the trace of the regular part of the Green function of $-\Delta + h$ and or on $b$. This is due to the perturbative term of order $1 + \delta$.