Conferences whose organisation I’m involved in:

• GAP Days Spring 2026, Faculty of Sciences of the University of Porto, Portugal. 4-8 May, 2026.

Conferences I plan to attend:

• International Meeting on Numerical Semigroups 2026, Akdeniz University, Antalya, Türkiye. 24 to 28 August 2026.
• Discrete Mathematics Days 2026, Faculty of Sciences of the University of Granada, Spain. 29 June – 1 July 2026.
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Conferences I attended recently:

• International Meeting on Commutative Monoids 2025, Universidad de La Laguna (Tenerife, Spain). 14th to 16 th July, 2025.
• GAP Days Spring 2025, Vrije Universiteit Brussel, Brussels (Belgium). 7-11 April, 2025.
• GAP Days Summer 2024, University of St Andrews, Scotland. 26-30 August 2024.
• International Meeting on Numerical Semigroups 2024, Jerez de la Frontera (Cádiz, Spain). 8 to 12 July, 2024. The pdf version of my presentation is available from this link.
• International Meeting on Commutative Monoids 2023, Universidade de Évora (Portugal). 18th to 20th July, 2023.
• INdAM workshop: International Meeting on Numerical Semigroups – Roma 2022, Roma, Italy. 13 to 17 June, 2022.
• 8th Iberian Mathematical Meeting, Seville, Spain. October 5-7, 2022.
• GAP Days “Spring” 2021, February 15th-19th, 2021, Virtual/Remote/Home Office
• GAP Singular meeting and school, August 15 — August 23, 2019, PfalzAkademie, Lambrecht, Germany
• II joint meeting Spain-Brazil in Mathematics, 11 to 14 December 2018, University of Cádiz, Spain.
• GAP Days Fall 2018, September 17 — September 21, 2018, University of Siegen, Germany.
• International Meeting on Numerical Semigroups, Cortona, Toscana, Italy. 3 to 7 September, 2018. The slides of my talk are available via this link.
• Encontro Nacional da Sociedade Portuguesa de Matemática — ENSPM 2018, Instituto Politécnico de Bragança, 9, 10 e 11 de julho de 2018, Bragança, Portugal.
• GAP Days Fall 2017, August 30 — September 8, 2017, University of Siegen, Germany. Pedro A. García-Sánchez gave a talk based on some joint work. The slides are available via this link.
• Ciência 2017: encontro com a ciência e a tecnologia em Portugal, Lisboa, July 3-5, 2017. The slides of my talk are available via this link.
• Workshop on Algebra and Geometry 2017 (Thematic week on Semigroups and applications), Badajoz, Spain, May 2-9, 2017
• Meeting of the Catalan, Spanish, Swedish Math Societies, 12-15 June 2017, Umeå, Sweden. The slides of my talk are available via this link.
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Conferences in whose organization I have been involved:

• International Conference on Semigroups and Automata 2016, 20-24/6/2016, Lisbon, Portugal.
• In the framework of the AMS / EMS / SPM International Meeting, 10-13/6/2016, Porto, Portugal, jointly with Pedro A. García-Sánchez, I organized a special session on “Commutative Monoids”. [See the Program. See also the slides of some talks.]
• 4th Iberian Mathematical Meeting, October 5-7, 2012, Universidad de Valladolid (mainly as a member of the scientific committee)
• Iberian Meeting on Numerical Semigroups Vila Real, July 18 – 20, 2012. An interview to the Scientific Committee made jointly with P. A. García-Sánchez has been published in the CIM [ Bulletin, number 33].
• Automata, Semigroups and Applications’ days, June, 2010.
• Iberian meeting on numerical semigroups – Granada 2010, Granada, Spain, February 3 – 5, 2010.
• International Conference on Semigroups and related topics, Porto, July 6 – 11, 2009. Issue 7 of Volume 21 of the International Journal of Algebra and Computation has been dedicated to that conference.
• School on Algebraic Theory of Automata, Lisbon, September 1 – 12, 2008.
• Iberian meeting on numerical semigroups – Porto 2008, March 17 – 19, 2008.

Some conferences I attended:

(Links to the slides presented are available in some cases.)

• • International Meeting on Numerical Semigroups with applications, Levico Terme, July 4th – 8th, 2016. [pdf]
  • NCMA 2015 Workshop on Non-Classical Models of Automata and Applications, August 31 & September 1, 2015, Porto, Portugal
  • AMS / EMS / SPM International Meeting, Porto, Portugal. 10-13 June, 2015. On the special session on “Commutative Monoids” (see the Program), I gave a talk entitled: a tutorial on the GAP package numericalsgps.]
  • Workshop on Groups and Semigroups, June 9, 2015, Porto, Portugal.
  • International Meeting on Numerical Semigroups, Cortona, Toscana, Italy. 8-13 September, 2014. [pdf]
  • GAP Days 2014, August 25-29, 2014, RWTH Aachen University, Germany.
  • Workshop on Computational Algebra 2014, Lisbon, Portugal. 21-23 July, 2014. I gave a talk on GAP and numerical semigroups
  • Jornadas de Sage/Python 2014 Jarandilla de la Vera (Cáceres), Spain. May 30 to June 1, 2014. I gave a talk on GAP packages
  • International Workshop “Parallel programming in GAP” August 18th-24th, 2013, University of St Andrews, Scotland. [pdf] [a picture]
  • Workshop on Semigroups 2012, May 23 – 25, 2012, Lisboa, Portugal. [pdf]
  • Groups and Semigroups: Interactions and Computations, July 25 – 29, 2011, Lisboa, Portugal. [pdf]
  • Soria Summer School on Computational Mathematics, July 13 – 24, 2009, Soria, Spain. [pdf]
  • International Conference on Geometric & Combinatorial Methods in Group Theory & Semigroup Theory, May 17 – 21, 2009, Lincoln-Nebraska, USA. [pdf]
  • Advanced GAP Workshop, September 11th – 15th 2007. Braunschweig, Germany.
  • Semigroups Workshop 2006, 5th – 9th September, 2006. St Andrews, UK.
  • ICMS’2006 Second International Congress on Mathematical Software, September 1 – 3, 2006, Castro Urdiales, Spain.
  • V JMDA: V Jornadas de Matemática Discreta y Algorítmica, July 12 – 14, 2006, Campus de Soria, Universidad de Valladolid, Spain.
  • Workshop on Semigroups and Automata: A Satellite Workshop to ICALP’05, July 16, 2005, Lisboa, Portugal.
  • International Conference on Semigroups and Languages in honour of the 65th birthday of Donald B. McAlister July 12 – 15, 2005, CAUL, Lisboa, Portugal.
  • International Meeting on Semigroup Theory and Related Topics June 26 – 28, 2003, Braga, Portugal.
  • Workshop Semigroups and Languages, November 27 – 29, 2002, Lisboa, Portugal.
  • ICSG: International Conference on Semigroups and Groups in Honor of the 65^th Birthday of John Rhodes, June 26 – 29, 2002, University of Porto, Portugal.
  • AAA 62: Workshop on General Algebra, from Thursday, June 14 – 17, 2001, Linz, Austria.
  • THEMATIC TERM: Semigroups, algorithms, automata and languages, May, June and July 2001, Portugal.
  • ISSAC 2000: International Symposium on Symbolic and Algebraic Computation, August 6 – 9, 2000, St Andrews, Scotland.
  • International Conference on Geometric and Combinatorial Methods in Group Theory and Semigroup Theory , May 15 – 19, 2000, Nebraska-Lincoln, USA.

Conferences I would like to have attended

• • GAP Days Summer 2022, Aachen, Germany. 17 to 21 September 2022.

• • Conference on Rings and Factorizations 2023, Graz, Austria. July 10–14, 2023.

• • 16th International Conference on Automata and Formal Languages, Eger, Hungary. September 5-7, 2023.

• • International Meeting on Numerical Semigroups, Jerez de la Frontera, Universidad de Cádiz, Spain. 23 to 26 June, 2020. [Canceled, due to the pandemics]

• • Conference on Algorithmic and Enumerative Combinatorics, Vienna, Austria, June 29-July 3, 2020.

• • Conference on Rings and Polynomials, Graz, Austria, July 20–25, 2020.

• • Semigroups and Groups, Automata, Logics, June 10–13, 2019, Cremona, Italy.

• • Computer Algebra in the Age of Types, August 13–17, 2018, RISC, Hagenberg, Austria.

• • International Congress of Mathematicians 2018 (ICM 2018), August 01–09, 2018, Rio de Janeiro, Brazil.

• • International Congress on Mathematical Software, 24–27 July 2018, Notre Dame (South Bend, Indiana) USA.

• • International Conference on Semigroups, July 11th to 14th, 2018, Lisboa, Portugal.

• • Jupyter in GAP and other CAS, June 4th – June 8th, 2018, University of St Andrews, Scotland.

• • Conference on Rings and Factorizations, February 19th to 23rd, 2018, Graz, Austria.

• • First Joint GAP-​Sage Days, GAP Coding sprint: Jan 13-16, 2016, University of St Andrews, Scotland.

• • First Joint GAP-​Sage Days, GAP-SageMath Workshop: Jan 18-22, 2016, University of St Andrews, Scotland.

• • Third GAP Days, September 19-23, 2015, NTNU Trondheim, Norway.

• • AutoMathA 2015, Jewels of Automata: from Mathematics to Applications, Leipzig, May 6–9, 2015, Germany.

• • GAP Days 2015, Spring, March 16-20, 2015, RWTH Aachen University, Germany.

• • International Conference on Geometric, Combinatorial and Dynamics aspects of Semigroup and Group Theory, Bar Ilan University, Israel, June 11 – 14, 2013, on the occasion of the 60th birthday of Stuart Margolis