Multiple solutions of double phase variational problems with variable exponentShi, Xiayang (Avtor) Rǎdulescu, Vicenţiu (Avtor) Repovš, Dušan (Avtor) Zhang, Qihu (Avtor) variable exponent elliptic operatorintegral functionalsvariable exponent Orlicz-Sobolev spacescritical pointThis paper deals with the existence of multiple solutions for the quasilinear equation ▫$$-\text{div} \mathbf{A} (x,\nabla u)+|u|^{\alpha(x)-2}u = f(x,u) \quad \text{in} \; \mathbb{R}^N,$$▫ which involves a general variable exponent elliptic operator ▫$\mathbf{A}$▫ in divergence form. The problem corresponds to double phase anisotropic phenomena, in the sense that the differential operator has various types of behavior like ▫$|\xi|^{q(x)-2} \xi$▫ for small ▫$|\xi|$▫ and like ▫$|\xi|^{p(x)-2} \xi$▫ for large ▫$|\xi|$▫, where ▫$1 < \alpha(\cdot) \le p(\cdot) < q(\cdot) < N$▫. Our aim is to approach variationally the problem by using the tools of critical points theory in generalized Orlicz-Sobolev spaces with variable exponent. Our results extend the previous works [A. Azzollini, P. d'Avenia and A. Pomponio, Quasilinear elliptic equations in ▫$\mathbb{R}^N$▫ via variational methods and Orlicz-Sobolev embeddings, Calc. Var. Partial Differential Equations 49 2014, 1-2, 197-213] and [N. Chorfi and V. D. Rǎdulescu, Standing wave solutions of a quasilinear degenerate Schrödinger equation with unbounded potential, Electron. J. Qual. Theory Differ. Equ. 2016 2016, Paper No. 37] from cases where the exponents ▫$p$▫ and ▫$q$▫ are constant, to the case where ▫$p(\cdot)$▫ and ▫$q(\cdot)$▫ are functions. We also substantially weaken some of the hypotheses in these papers and we overcome the lack of compactness by using the weighting method.20202020-10-13 10:26:26Članek v reviji121505sl