Precup, RaduRodríguez López, Jorge2025-12-292025-12-292020Nonlinear Analysis Volume 199, October 2020, 1119580362-546Xhttps://hdl.handle.net/10347/44794In this paper, we develop a fixed point index theory for decomposable multivalued maps, that is, compositions of two multivalued nonlinear upper semicontinuous maps. As an application, this fixed point index theory is combined with the method of lower and upper solutions in order to obtain new existence, localization and multiplicity results for ϕ-Laplacian problems with discontinuous nonlinearities and nonlinear functional boundary conditions.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Fixed point index theoryDiscontinuous differential equationMultiple solutionsϕ-Laplacian equationLower and upper solutionsjournal article10.1016/j.na.2020.111958open access