Ignacio Ojeda Martínez de Castilla 

Research

• Google Scholar.
• MR Author ID: 668270.
• ORCID: 0000-0003-3173-5934.
• ResearcherID: I-1450-2015.
• Scopus AI: 6507535437.

Papers in Journals and Book Chapters

• Ojeda, Ignacio; Rosales, José Carlos. The multiples of a numerical semigroup. arXiv:2402.04413 [math.GR].
• Colaço, Isabel; Ojeda, Ignacio. Minimal free resolution of generalized repunit algebras. arXiv:2312.06013 [math.AC].
• Branco, Manuel B.;Ojeda, Ignacio; Rosales, José Carlos. Arithmetic varieties of numerical semigroups. arXiv:2311.13500 [math.AC].
• Bravo, José Luis; Fernandez, Manuel; Ojeda, Ignacio. Hilbert number for a family of piecewise nonautonomous equations. Qualitative Theory of Dynamical Systems 23, article n. 119, 2024 arXiv:2307.15578 [math.DS].
• García Marco, Ignacio; García-Sánchez, Pedro A.; Ojeda, Ignacio; Tatakis, Christos Universally free numerical semigroups. Journal of Pure and Applied Algebra 228(5), 2024. arXiv:2303.06474 [math.AC].
• Jafari, Raheleh; Ojeda, Ignacio. On the depth of simplicial affine semigroup rings. Collectanea Mathematica, 2024.arXiv:2307.16501 [math.CA].
• Bravo, José Luis; Fernandez, Manuel; Ojeda, Ignacio. Stability of singular limit cycles for Abel equations revisited Journal of Differential Equations 379 (15), 2024. arXiv:2302.13642 [math.CA].
• Branco, Manuel B.;Colaço, Isabel; Ojeda, Ignacio. The Frobenius problem for generalized repunit numerical semigroups. Mediterranean Journal of Mathematics 20, Article number: 16 (2023). arXiv:2112.01106 [math.AC].
• Bravo, José Luis; Calderon, Luis Ángel; Ojeda, Ignacio. Rational Limit Cycles of Abel Differential Equations. Electronic Journal of Qualitative Theory of Differential Equations 47, 2023, 1-13. arXiv:2302.10743 [math.CA].
• Bravo, José Luis; Calderon, Luis Ángel; Fernandez, Manuel; Ojeda, Ignacio. Rational Solutions of Abel Differential Equations. Journal of Mathematical Analysis and Applications 515(1), 2022 arXiv:2109.07853 [math.CA].
• Marijuán, Carlos; Ojeda, Ignacio; Vigneron-Tenorio, Alberto. A note on decomposable and reducible integer matrices. Symmetry (2021) no. 13(7), 1125. arXiv:2003.01453 [math.GR].
• Branco, Manuel B.; Ojeda, Ignacio; Rosales, José Carlos. The set of numerical semigroups of a given multiplicity and Frobenius number. Portugaliae Mathematica (2021) no. 78(2), 147–167. arXiv:1904.05551 [math.CO].
• Branco, Manuel B.;Colaço, Isabel; Ojeda, Ignacio. Minimal binomial systems of generators for the ideals of certain monomial curves. Mathematics 2021, 9(24), 3204. arXiv:2111.03714 [math.AC].
• García-Sánchez, Pedro A.; Llena, David; Ojeda, Ignacio. Critical binomial ideals of Norhtcott type Journal of the Australian Mathematical Society (2021) no. 110, 48–70. arXiv:1705.10268 [math.CA].
• Navarro, Alberto; Navarro, José; Ojeda, Ignacio. Commutative monoids and their corresponding affine k-schemes. Semigroup Forum (2020) no. 101, 421-434.
• Ojeda, Ignacio; Rosales, José Carlos. The arithmetic extensions of a numerical semigroup. Communications in Algebra (2020) no. 48, 3707-3715.arXiv:2003.05193 [math.AC]
• García-García, Juan Ignacio; Ojeda, Ignacio; Vigneron-Tenorio, Alberto; Rosales, José Carlos. On pseudo-Frobenius elements of submonoids of N^d. Collectanea Mathematica (2020) no.71, 189–204. arXiv:1903.11028 [math.AC].
• García-Sánchez, Pedro A.; Ojeda, Ignacio. Almost symmetric numerical semigroups with high type. Turkish Journal of Mathematics (2019), no. 43, 2499.2510. arXiv:1904.02987 [math.GR].
• Branco, Manuel B.; Ojeda, Ignacio; Rosales, José Carlos. Almost symmetric numerical semigroups with given Frobenius number and type J. Algebra Appl. 18 (2019), no. 11, 1950217. arXiv:1806.11097 [math.CA].
• Bravo, José Luis; Fernández García-Hierro, Manuel; Ojeda, Ignacio; Sánchez Fernández, Fernando. Uniqueness of Limit Cycles for Quadratic Vector Fields Discrete and Continuous Dynamical Systems, 39 (2019), no. 1, 483-502. arXiv:1709.00903 [math.CA].
• Matusevich, Laura F.; Ojeda, Ignacio. Binomial Ideals and Congruences on N^n . G.M. Greuel (ed.) et al., Singularities, Algebraic Geometry, Commutative Algebra, and Related Topics. Festschrift for Antonio Campillo on the Occasion of his 65th Birthday. Springer, 429-454 (2018). arXiv:2003.03861 [math.AC].
• Ojeda, Ignacio; Vigneron-Tenorio, Alberto; The short resolution of a semigroup algebra. Bulletin of the Australian Mathematical Society, 96 (2017), no. 3, 400-411. arXiv:1512.00345 [math.RA].
• Assi, Abdallah; García-Sánchez, Pedro A.; Ojeda, Ignacio. Frobenius vectors, Hilbert series and gluings . arXiv:1311.1988 [math.AC]. Journal of Commutative Algebra, 7 (2015), no. 3, 317-335.
• Márquez-Campos, Guadalupe; Ojeda, Ignacio; Tornero, José M.; On the computation of the Apéry set of numerical monoids and affine semigroups. Semigroup Forum 91 (2015), no. 1, 139-158. arXiv:1907.01222[math.CO].
• Ojeda, Ignacio. Kronecker Square Roots and The Block vec Matrix. Amer. Math. Monthly 121 (2015), no. 1, 60-64. arXiv:1310.8149 [math.GM]
• Katsabekis, Anargyros; Ojeda, Ignacio. An indispensable classification of monomial curves in A^4(k). Pacific J. Math. 268 (2014), no. 1, 96-116. arXiv:1103.4702[math.AC]
• Garcia-Sanchez, Pedro A.; Ojeda, Ignacio; Sanchez-R.-Navarro, Alfredo. Factorization invariants in half-factorial affine semigroups. Int. J. Algebra Comput. 23, 111 (2013) arXiv:1207.5838 [math.AC]
• Garcia-Sanchez, Pedro A.; Ojeda, Ignacio; Rosales, José Carlos. Affine semigroups having a unique Betti element. J. Algebra Appl. 12, 1250177 (2013) [11 pages] arXiv:1203.4138 [math.AC]
• Ojeda, Ignacio. Binomial canonical decomposition of binomial ideals. Communications in Algebra, 39 (2011), no. 10, 3722-3735. arXiv:1003.1701[math.AC]
• Garcia-Sanchez, Pedro A.; Ojeda, Ignacio. Uniquely presented finitely generated commutative monoids. Pacific J. Math. 248 (2010), no. 1, 91-105. arXiv:0907.4241[math.AC]
• Ojeda, Ignacio; Vigneron-Tenorio, Alberto Indispensable binomials in semigroup ideals . Proc. Amer. Math. Soc. 138 (2010), 4205-4216. arXiv:0903.1030[math.AC]
• Notari, Roberto; Ojeda, Ignacio; Spreafico, Maria Luisa. Doubling rational normal curves. Alonso, María Emilia (ed.) et al., Liaison, Schottky problem and invariant theory. Remembering Federico Gaeta. Basel: Birkhauser. Progress in Mathematics 280, 149-187 (2010).arXiv:0812.2578[math.AG]
• Ojeda, Ignacio; Vigneron-Tenorio, Alberto Simplicial complexes and minimal free resolution of monomial algebras. J. Pure Appl. Algebra 214 (2010), no. 6, 850-861.arXiv:0810.4836[math.AC]
• Ojeda Martínez de Castilla, Ignacio. Examples of generic lattice ideals of codimension 3. Comm. Algebra 36 (2008), no. 1, 279-287.
• Notari, R.; Ojeda, I. Even $G$-liaison classes of some unions of curves. J. Pure Appl. Algebra 204 (2006), no. 2, 389-412.
• Notari, Roberto; Ojeda, Ignacio; Spreafico, Maria Luisa. Non degenerate projective curves with very degenerate hyperplane section. Math. Z. 251 (2005), no. 2, 443-473.
• Ojeda Martínez de Castilla, Ignacio; Pisón Casares, Pilar. On the hull resolution of an affine monomial curve. J. Pure Appl. Algebra 192 (2004), no. 1-3, 53-67.
• Ojeda Martínez de Castilla, Ignacio; Piedra Sánchez, Ramón. Index of nilpotency of binomial ideals. J. Algebra 255 (2002), no. 1, 135-147.
• Ojeda Martínez de Castilla, Ignacio; Sánchez, Ramón Peidra. Cellular binomial ideals. Primary decomposition of binomial ideals. J. Symbolic Comput. 30 (2000), no. 4, 383-400.

Other publications:

• Book of abstracts. II Iberian Mathematical Meeting (I. Ojeda, ed.), 2008, ISBN: 978-84-692-3591-1.
• Ojeda Martínez de Castilla, Ignacio; Piedra Sánchez, Ramón Pilar Pisón Casares, in memoriam. (Spanish) Gac. R. Soc. Mat. Esp. 10 (2007), no. 3, 637-642.
• Reviews for Mathematical Reviews/MathSciNet.
• Ph. D Thesis. Ideales Binomiales y Aplicaciones (Spanish), Universidad de Sevilla 2000. ISBN: 84-688-5916-8

International Courses Taught:

• Third EACA International School on Computer Algebra and its Applications, Sevilla (SPAIN), 2016.
• Cuarto Curso de Estadística Algebraica, Logroño (SPAIN), 2011.
• Fourth Meeting for Young Mathematicians in Sedano, Sedano (Burgos, SPAIN), 2008.

Software:

• Contributor of the GAP package NumericalSgps.
• apery.lib, Singular library for the computation of the apery set and the frobenius number of a numerical semigroup (2015).
• binomialCD.m2, Macaulay2 package for a cellular decomposition (1999). This package has been improved by T. Kahle and included in Kahle's Macaulay2 package binomial.m2

Organizing/Scientific Committees:

• International Meeting on Numerical Semigroups 2024 (2024). Jerez de la Frontera (Cádiz, Spain).
• 20th winter school in Dynamical Systems of the DANCE (Dinámica, Atractores y Nolinealidad: Caos y Estabilidad) Spanish network. (2024). Badajoz (Spain).
• II Congreso Luso-Extremadurense de Ciencia y Tecnología (2018). Badajoz (Spain).
• Workshop on Algebra and Geomertry (2012-2014 and 2017). Badajoz (Spain).
• II Joint meeting Évora-Extremadura on Mathematics (2017). Évora (Portugal). Ver : vídeo, noticia .
• I Joint meeting Évora-Extremadura on Mathematics (2016). Badajoz (Spain). Ver : noticia .
• Toric Geometry Seminars (2007-2010). Jarandilla de la Vera (Cáceres).
• International School of Combinatorics "Pilar Pisón Casares" 2010. Seville (Spain), January 25-30, 2010.
• II Iberian Mathematical Meeting Badajoz (Spain), October 3-5, 2008.
• International Conference on Commutative, Combinatorial and Computational Algebra in Honour of Pilar Pisón Casares Seville (Spain), February 11 - 16, 2008.