We study a nonlinear Neumann boundary value problem associated to a nonhomogeneous differential operator. Taking into account the competition between the nonlinearity and the bifurcation parameter, we establish sufficient conditions for the existence of nontrivial solutions in a related Orlicz–Sobolev space.

The nonlinear eigenvalue problem for p-Laplacian $$\left\{\begin{array}{c}-{div\left(a\left(x\right)\right|\nabla u|}^{p-2}{\nabla u)=\lambda g\left(x\right)|u|}^{p-2}u\text{in}{ℝ}^N,u>0\text{in}{ℝ}^N,\underset{\left|x\right|\to \infty }{lim}u\left(x\right)=0,\hfill \end{array}\right.$$ is considered. We assume that $1<p<N$ and that $g$ is indefinite weight function. The existence and $C^{1,\alpha }$-regularity of the weak solution is proved.

We investigate the behavior of weak solutions to the nonlocal Robin problem for linear elliptic divergence second order equations in a neighborhood of a boundary corner point. We find an exponent of the solution's decreasing rate under minimal assumptions on the problem coefficients.

In this article, we study the existence of nontrivial weak solutions for the following boundary value problem: $$-{\Delta }_{\gamma }u=f(x,u)\text{in}\Omega ,u=0\text{on}\partial \Omega ,$$ where $\Omega$ is a bounded domain with smooth boundary in ${ℝ}^N$, $\Omega \cap \{x_j=0\}\ne \varnothing$ for some $j$, ${\Delta }_{\gamma }$ is a subelliptic linear operator of the type $${\Delta }_{\gamma }:=\sum _{j=1}^N{\partial }_{x_j}\left({\gamma }_j^2{\partial }_{x_j}\right),{\partial }_{x_j}:=\frac{\partial }{\partial x_j},N\ge 2,$$ where $\gamma \left(x\right)=({\gamma }_1\left(x\right),{\gamma }_2\left(x\right),\cdots ,{\gamma }_N\left(x\right))$ satisfies certain homogeneity conditions and degenerates at the coordinate hyperplanes and the nonlinearity $f(x,\xi )$ is of subcritical growth and does not satisfy the Ambrosetti-Rabinowitz (AR) condition.

The purpose of this paper is to derive norm inequalities for potentials of the formTf(x) = ∫(Rn) f(y)K(x,y)dy,     x ∈ Rn,when K is a Kernel which satisfies estimates like those that hold for the Green function associated with the degenerate elliptic equations studied in [3] and [4].

We are concerned with the null controllability of a linear coupled population dynamics system or the so-called prey-predator model with Holling type I functional response of predator wherein both equations are structured in age and space. It is worth mentioning that in our case, the space variable is viewed as the “gene type” of population. The studied system is with two different dispersion coefficients which depend on the gene type variable and degenerate in the boundary. This system will be governed...