Resumen: A singularly perturbed elliptic problem, with non-smooth inflow or non-smooth outflow boundary conditions, is examined. A decomposition of the continuous solution is constructed, whose components identify the various types of layer functions that can exist in the solution. Parameter-explicit pointwise bounds on the first three partial derivatives of these components are established. An appropriate Shishkin mesh is identified for the problem and this is combined with upwinding to form a numerical method. Parameter-uniform error bounds are deduced. Numerical results are presented to illustrate the performance of the numerical method. Idioma: Inglés DOI: 10.1016/j.cam.2024.116094 Año: 2024 Publicado en: Journal of Computational and Applied Mathematics 451 (2024), 116094 [14 pp.] ISSN: 0377-0427 Factor impacto JCR: 2.6 (2024) Categ. JCR: MATHEMATICS, APPLIED rank: 35 / 343 = 0.102 (2024) - Q1 - T1 Factor impacto SCIMAGO: 0.688 - Computational Mathematics (Q2) - Applied Mathematics (Q2)