Fernández Tojo, Fernando Adrián2025-01-092025-01-092018F. Adrián F. Tojo, A constructive approach towards the method of solution-regions, Journal of Mathematical Analysis and Applications, Volume 472, Issue 2, 2019, Pages 1803-1819https://hdl.handle.net/10347/38457In this work we develop the theory of solution-regions with a constructive approach. We also extend the theory to the case of general linear conditions and provide various sets of sufficient hypotheses for existence and multiplicity results.engAttribution-NonCommercial-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/System of First Order Differential EquationsMultiple SolutionsFixed Point IndexGeneral Boundary ConditionsSolution-RegionsUpper and Lower Solutionsjournal article10.1016/j.jmaa.2018.12.024open access