Resumen: The combined matrix is a very useful concept for many applications. Almost strictly sign regular (ASSR) matrices form an important structured class of matrices with two possible zero patterns, which are either type-I staircase or type-II staircase. We prove that, under an irreducibility condition, the pattern of zero and nonzero entries of an ASSR matrix is preserved by the corresponding combined matrix. Without the irreducibility condition, it is proved that type-I and type-II staircases are still preserved. Illustrative numerical examples are included. Idioma: Inglés DOI: 10.1016/j.cam.2018.09.029 Año: 2018 Publicado en: Journal of Computational and Applied Mathematics 354 (2018), 144 - 151 ISSN: 0377-0427 Factor impacto JCR: 1.883 (2018) Categ. JCR: MATHEMATICS, APPLIED rank: 47 / 254 = 0.185 (2018) - Q1 - T1 Factor impacto SCIMAGO: 0.849 - Computational Mathematics (Q2) - Applied Mathematics (Q2)