Abstract
In this article, we investigate multiplicity results for Choquard-Kirchhoff type equations, with Hardy-Littlewood-Sobolev critical exponents,
$$\begin{array}{}
\displaystyle -\left(a + b\int\limits_{\mathbb{R}^N} |\nabla u|^2 dx\right){\it\Delta} u =
\alpha k(x)|u|^{q-2}u +
\beta\left(\,\,\displaystyle\int\limits_{\mathbb{R}^N}\frac{|u(y)|^{2^*_{\mu}}}{|x-y|^{\mu}}dy\right)|u|^{2^*_{\mu}-2}u,
\quad
x \in \mathbb{R}^N,
\end{array}$$
where a > 0, b ≥ 0, 0 < μ < N, N ≥ 3, α and β are positive real parameters,
$\begin{array}{}
2^*_{\mu} = (2N-\mu)/(N-2)
\end{array}$ is the critical exponent in the sense of Hardy-Littlewood-Sobolev inequality, k ∈ Lr(ℝN), with r = 2∗/(2∗ − q) if 1 < q < 2* and r = ∞ if q ≥ 2∗. According to the different range of q, we discuss the multiplicity of solutions to the above equation, using variational methods under suitable conditions. In order to overcome the lack of compactness, we appeal to the concentration compactness principle in the Choquard-type setting.
On the existence of an extremal function in critical Sobolev trace embedding theorem
