Liu, ZhenhaiPapageorgiou, Nikolaos S.2023-04-252023-04-252022-07-28Liu, Z., & Papageorgiou, N. S. (2022). Double phase equations with an indefinite concave term. <i>Electronic Journal of Differential Equations, 2022</i>(55), pp. 1-10.1072-6691https://hdl.handle.net/10877/16645We consider a Dirichlet problem having a double phase differential operator with unbalanced growth and reaction involving the combined effects of a concave (sublinear) and of a convex (superlinear) terms. We allow the coefficient ℇ ∈ L∞(Ω) of the concave term to be sign changing. We show that when ‖ℇ‖∞ is small the problem has at least two bounded positive solutions. ℇText10 pages1 file (.pdf)enAttribution 4.0 InternationalUnbalanced growthGeneralized Orlicz spacesPositive solutionConcave-convex problemMountain pass theoremArticle