Existence and multiplicity of solutions for Schrödinger–Kirchhoff type problems involving the fractional p(⋅)$p(\cdot )$ -Laplacian in RN$\mathbb{R}^{N}$

We are concerned with the following elliptic equations with variable exponents: $$ M \bigl([u]_{s,p(\cdot,\cdot)} \bigr)\mathcal{L}u(x) +\mathcal {V}(x) \vert u \vert ^{p(x)-2}u =\lambda\rho(x) \vert u \vert ^{r(x)-2}u + h(x,u) \quad \text{in } \mathbb {R}^{N}, $$ where $[u]_{s,p(\cdot,\cdot)}:=\int_{\mathbb {R}^{N}}\int_{\mathbb {R}^{N}} \frac{|u(x)-u(y)|^{p(x,y)}}{p(x,y)|x-y|^{N+sp(x,y)}} \,dx \,dy$ , the operator $\mathcal{L}$ is the fractional $p(\cdot)$ -Laplacian, $p, r: {\mathbb {R}^{N}} \to(1,\infty)$ are continuous functions, $M \in C(\mathbb {R}^{+})$ is a Kirchhoff-type function, the potential function $\mathcal {V}:\mathbb {R}^{N} \to(0,\infty)$ is continuous, and $h:\mathbb {R}^{N}\times\mathbb {R} \to\mathbb {R}$ satisfies a Caratheodory condition. Under suitable assumptions on h, the purpose of this paper is to show the existence of at least two non-trivial distinct solutions for the problem above for the case of a combined effect of concave–convex nonlinearities. To do this, we use the mountain pass theorem and variant of the Ekeland variational principle as the main tools.