Invited Talks

    2022

  1. The Universal Spectrum of the H-join of arbitrary graphs - the walk matrix approach Encontro Conjunto Brasil-Portugal em Matemática, UFBA, Salvador, Bahia, 14-20 de Agosto 2022, and XXX Congreso de Matemática Capricórnio - COMCA 2022, 3-5 de Agosto 2022, Iquique, Chile.

    2. 2021

  2. The H-join of arbitrary families of graphs Graph Theory Day, Christ University, Bengaluru, India, June 10, 2021.

    3. 2020

  3. On the 4th Moore Graph with diameter 2 Annual meeting of the Center for Research & Development in Mathematics and Applications (CIDMA), Department of Mathemarics, University of Aveiro, January 22-23, 2020.

    4. 2019

  4. Contributions to the isomorphism problem. Combinatória no Outono - nos 65 anos de António Guedes de Oliveira, Departamento de Matemática da Universidade de Aveiro - 25 of September, 2019.
  5. Recent and old results on (k,t )-regular sets and their applications. XXVIII Congreso de Matemáticas Capricornio, COMCA 2019, Universidad de La Serena, July 31- August 02, 2019, La Serena, Chile.
  6. An overview of (k,\tau)-regular sets and their applications. International Conference on Emerging Trends in Graph Theory, ICETGT-2019. Department of Mathematics, Christ University, 27-28, February 2019, Bangalore, India.

    7. 2017

  7. Lexicographic polynomials of graphs and their spectra, a joint work with P. Carvalho, P. Rama, S.K. Simic and Z. Stanic, Mini-Symposia on Spectral Graph Theory, 2017 Meeting of the International Linear Algebra Society. Department of Mathematics, Iowa State University, July 24-28, Iowa, USA.

    8. 2016

  8. Star sets/star complements of graph eigenvalues and simplex like techniques in combinatorial problems, ICCOPT - The Fith International Conference on Continouous Optimization, 6-11 August 2016, National Olympics Memorial Youth Center (NYC), Yoyogi and National Graduate Institute for Policy Studies, Roppongi, Tokyo, Japan.

    9. 2014

  9. A simplex-like approach to the maximum stable set of Q-graphs based on star sets and star complements, a joint work with Carlos Luz, XXIII Congreso de Matemática Capricornio - COMCA, Universidad de Atacama, Compiapó, Chile, 6 - 8 of August, 2014.

    10. 2013

  10. Convex quadratic programming in graphs - links betweeen continuous and discrete problems (keynote lecture), 2nd International Conference on Operations Research and Enterprise Systems - ICORES 2013, February 16-18, Barcelona, Spain.

    11. 2011

  11. A influência da matemática na II Guerra Mundial, with António F. Pereira,  Encontro de antigos alunos do Departamento de Matemática da Universidade de Aveiro, May 28, Aveiro,Portugal (the same talk was  presented during the Science and Technoloy Open Week of Aveiro University, see Seminars).

    12. 2010

  12. Generalização de um resultado de Fiedler com aplicações na teoria espectral dos grafos, Encontro de Algebristas Portugueses 2010, September 16-18, Covilha, Portugal.
  13. Graph eigenvalues in combinatorial optimization (the same talk presented in the Coimbra Meeting below),16th Conference of the International Linear Algebra, "Mini-symposium on Graph Spectra", organized by Dragan Stevanovic and Vladimir Nikiforov, June 21-25, Pisa, Italy.
  14. Graph eigenvalues in combinatorial optimization, Coimbra Meeting on 0-1 Matrix Theory and Related Topics, June 17-19, Coimbra, Portugal.
  15. A survey on spectral graph theory techniques in Combinatorial Optimization, ALIO -INFORMS Joint International Meeting 2010, "Mini-symposium on Graph Spectra with Applications on Combinatorial Optimization", organized by Nair Abreu, June 6-9, Buenos Aires, Argentina.

    16. 2009

  16. Graph eingenvalues and upper bounds on the order of k-regular induced subgraphs, with Peter Rowlinson, XIX Congreso de Matematica Capricornio - COMCA 2009, Universidade Catolica del Norte, Antofagasta, Chile, 5-7 Agust.
  17. Spectral upper bounds on the size of k-regular induced subgraphs, with Sofia Pinheiro, Workshop on Algorithmic Graph Theory, University of Warwick, 23-25 March.
  18. A natureza combinatória de muitos problemas práticos, 1as Jornadas de Física e Matemática do ISEC, Coimbra, 14 de Janeiro. Resumo (in Portuguese)

    19. 2008

  19. A survey on (k,t)-regular sets and their applications, Workshop on Spectral Graph Theory with Applications on Computer Science, Combinatorial Optimization and Chemistry, Rio de Janeiro, December 1-4. Slides

    20. 2007

  20. Graphs whose stability number is easily determined, Conference on Graph Theory on the Occasion of the 80th Birthday of Professor Horst Sachs, March 27-30, Ilmenau.Slides

    21. 2006

  21. Continuous optimization polynomial-time upper bounds on the stability number of graphs, with Sofia Pinheiro. Iberian Conference in Optimization, Coimbra, 16-18 November. Slides.
  22. The class of graphs with convex-qp stability number, International mathematical conference - Topics in mathematical analysis and graph theory (MAGT), Belgrade, August 31 - September 4. Slides.

    23. 2002

  23. On graphs with stability number equal to the optimal value of a convex quadratic programming problem. Workshop Latino-Americano de Cliques em Grafos, Rio de Janeiro, Brasil, April 17-19. Abstract.
  24. Problemas combinatórios em conjuntos parcialmente ordenados. Session on Optimization, organized by Joaquim J. Júdice, Encontro Nacional da SPM, Coimbra, Portugal, February 5-8. Resumo.

    25. 2001

  25. Stable sets, matchings and related results. Session to honour Professor Ernesto Martins organized by Douglas R. Shier, Optimization 2001, Aveiro, Portugal, June 23-25. Abstract.
  26. Extensions of a Motzkin-Straus result on the stability number of graphs. Workshop on MaxClique'01, Klagenfurt, Austria, May 31 - June 3. Abstract.

    27. 2000

  27. Validation in alternative selection problems - Part I: tools from combinatorics and graph theory, with J. Freire de Sousa. Session on Multiple Criteria Optimization organized by Ralph Steuer, 4th International Conference on Operations Research, Habana, Cuba, March 7 - 13. Abstract.
  28. Validation in alternative selection problems - Part II: analysis of an application in the acquisition of urban buses, with J. Freire de Sousa. Session on Multiple Criteria Optimization organized by J. N. Clímaco, 4th International Conference on Operations Research, Habana, Cuba, March 7-13. Abstract.

    29. 1999

  29. On a parallel implementation of the generalized simplex method, with João P. Costa and João C. Clímaco. Session on Hybrid Methods in Real and Integer Linear Programming organized by Pierre Tolla, IFORS'99, Beijing, China, August 16-20. Abstract.
  30. Multicriteria models of storage assignement problems. Session on Multicriteria Combinatorial Optimization organized by Jean-Pierre Brans and Theodor Stewart, IFORS'99, Beijing, China, August 16-20. Abstract.

    31. 1998

  31. The overflow traffic from the Erlang-B system - what convexity properties?, with J. Sá Esteves and J. Craveirinha, 1º Seminário em Matemática em Telecomunicações, IT, Coimbra, Portugal, September 28-29. Abstract.
  32. Temas e problemas em combinatória. Session on Operational Research, organized by Joaquim J. Júdice, Encontro Nacional da SPM, Braga, Portugal, February 9-12. Resumo.

    33. 1997

  33. A quadratic programming approach to the determination of an upper bound on the weighted stability number, with C. J. Luz. Session on linear and nonlinear optimization, organized by Joaquim J. Júdice, Joint International Meeting EURO - INFORMS, Barcelona, Spain, July 14-17. Abstract.

    34. 1993

  34. The well-known linear programming approachs and a generalization of the simplex method, with J. N. Clímaco (Portuguese National Contribution). IFORS'93, Lisboa, Portugal, July 12-16. Abstract.

Seminars

    2015

  1. Linear Programming on Graphs Through Star Sets and Star Complement, a joint work with Carlos Luz and Fátima Pacheco, Seminário de Teoria Espectral dos Grafos, UFRJ, May 11, Rio de Janeiro, Brazil.

    2. 2014

  2. Effiient domination through eigenvalues, joint work with Vadim V. Lozin and Carlos J. Luz, Colloquium Program, Mathematics Department,Universidad Catolica del Norte, July 24, 2014, Antofagasta, Chile.
  3. Finding a maximum order k-regular induced subgraph: a challenge between continuous and discrete problems, Colloquium Program, Mathematics Department,Universidad Catolica del Norte, January 16, Antofagasta, Chile.

    4. 2012

  4.  The influence of mathematics in world war two, with António F. Pereira, Programa Coloquios en Matematica del Departamento de Matematicas de la Facultad de Ciencias de la Universidad Católica del Norte, Antofagasta, Chile, Jabuary 19 (the same talk was presented in 2010 during the Science and Technoloy Open Week of Aveiro University).

    5. 2010

  5.  A influência da matemática na II Guerra Mundial, with António F. Pereira, Semana Aberta da Ciência e Tecnologia da Universidade de Aveiro, 22-26 de Novembro.
  6. Partial colorings, posets and chromatic polynomials, Universidade de Coimbra, Linha de Álgebra e Combinatória do CMUC, March 3, 2010 e Universidade de Lisboa, Seminário do Centro de Estruturas Lineares e Combinatórias, March 15, 2010.
  7. Conjuntos parcialmente ordenados, polinómios cromáticos e Sudoku, Universidade Federal do Rio de Janeiro, COPPE/UFRJ, Rio de Janeiro, Brasil, 1 de Fevereiro de 2010 (this seminar, in Portuguese, is the same presented at Universidade do Minho, Braga, 19 de Janeiro 2009).

    8. 2009

  8. Convex quadratic techniques for optimization in graphs – a survey, Seminário de Optimización do Centro de Modelamiento Matematico (CMM), Universidade do Chile, Santiago de Chile, Agust 29.
  9. Conjuntos parcialmente ordenados, polinómios cromáticos e Sudoku, Colóquio de Matemática, Universidade do Minho, Braga, 19 de Janeiro. Slides (in Portuguese)

    10. 2008

  10. Posets, Matching and Partial Colouring. Seminar at the Department of Mathematics, Faculty of Science, University of Malta, 30 April Abstract.
  11. Spectral Properties and Applications of (k,t)--regular sets: an overview. Seminar at the Department of Mathematics, Faculty of Science, University of Malta, 28 April Abstract.

    12. 2007

  12. Convex quadratic programming techniques on graphs and related spectral results. Seminar on Applied and Industrial Mathematics of the Mathematical Institute of Serbian Academy of Sciences and Arts, June 5, Belgrade. Abstract.

    13. 2005

  13. A matemática e os seus problemas, Semana da Ciência e Tecnologia, Universidade de Aveiro, Portugal, 21-27 de Novembro. Resumo; Full text (in Portuguese).

    14. 2004

  14. Graphs with convex-QP stability number. Seminar of Department of Discrete Mathematics, Adama Mickiewicza University, January 6, Poznan, Poland. Slides.
  15. Moore graphs and (k,t)-regular sets.. Seminar on Applied Mathematics, Institute of Mathematics, Poznan University of Technology, January 7, Poznan, Poland. Abstract.

    16. 2003

  16. Uma abordagem algébrica de grafos fortemente regulares. Sessão de Homenagem ao Professor Mário da Silva Rosa, Coimbra, Portugal, October 15. Resumo; Slides (in Portuguese).

    17. 2002

  17. O quarto grafo de Moore. Seminar on Combinatorics of Pure Mathematics Department of Porto University, Porto, Portugal, December 3. Resumo.

    18. 2000

  18. A Matemática e o Desenvolvimento Tecnológico. Semana da Ciência e Tecnologia, Universidade de Aveiro, Portugal, 21 de Novembro. Resumo.
  19. Aplicações da Matemática Discreta. Portuguese Mathematical Society Seminars to celebrate the World Mathematical Year. Escola Secundária Clara de Resende, Porto, Portugal, May 10. Resumo.

    20. 1999

  20. Resultados espectrais em grafos e aplicações. Seminar of Numerical Analysis, Optimization and Applications Group of Mathematics Department of Coimbra University. Coimbra, Portugal. Resumo.

    21. 1997

  21. Grafos e problemas combinatórios. Seminar of Applied Mathematics to Telecommunications, IT, Coimbra, Portugal.

    22. 1994

  22. O regresso à fronteira em optimização linear. Seminar of Applied Mathematics Department of Porto University, Porto, Portugal. Resumo.

    23. 1991

  23. Nova aproximaçãoà optimização linear a partir de uma generalização do método simplex. Seminar of APDIO Optimization Group. Círculo Universitário do Porto, Porto, Portugal.

Debates and panel discussions

    2013

  1. The teaching of mathematics in Engineering, Economics and Natural Sciences courses 1rst Portuguese Meeting on Mathematics for Industry, June 6-8, 2013, Porto, Portugal.

    2. 2006

  2. A Matemática na Engenharia e na Indústria, with José Carlos Quadrado (ISEL) and J. Norberto Pires (UC), Encontro Nacional da Sociedade Portuguesa de Matemática, Lisbon, June 20 - 23.

    2004

  3. Reflexões sobre o Ensino da Pesquisa Operacional, with João Clímaco and Jorge Freire de Sousa. XXXVI SBPO - Simpósio Brasileiro de Pesquisa Operacional, São João del-Rei, MG, Brasil, November 23-26. Full text (in Portuguese).

    4. 2000

  4. A IO no sistema de ensino, with João Clímaco, Rui Guimarães and Victor Vidal. IO 2000 - IX Congresso da Associação Portuguesa de Investigação Operacional (APDIO), Instituto Politécnico de Setúbal, April 16-19.

Contributions

    2022

  1. The univesral spectrum of the H-join of arbitrary graphs - the universal adjacency spectrum, 9th INternational Conference on Matrix Analysis and Applications (ICMAA 2022). June 15-17, 2022, University of Aveiro, Portugal.

    2. 2018

  2. A survey on graphs with convex quadratic stability number, XIX Latin-Iberoamerican Conference on Operations Research - CLAIO2018. Lima, Perú, September 24-27, 2018.

    3. 2017

  3. Lexicographic polynomials of graphs, a joint work with P. Carvalho, P. Rama, S.K. Simic and Z. Stanic, Optimization 2017. Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal, September 6-8, 2017.
  4. Grafos com número de estabilidade quadrático convexo: principais resultados e problemas em aberto, XVIII Congresso da APDIO - IO2017. Valença, Portugal, 28-30 Jun/2017.

    5. 2016

  5. Programação convexa em grafos - uma abordagem espectral e combinatória, Encontro Nacional da SPM 2016, Escola Superior de Tecnologia do Barreiro do Instituto Politécnico de Setúbal, Barreiro, Portugal, 11-13 de Julho de 2016.
  6. Spectral and combinatorial properties of lexicographic powers of graphs, a joint work with Nair Abreu, Paula Carvalho and Cybele Vinagre, Spectra of graphs and applications 2016, in honour of Prof. Dragos Cvetkovic, May 18–20,2016, Serbian Academy of Sciences and Arts, Belgrade, Serbia.

    7. 2015

  7. Linear Programming on Graphs Through Star Sets and Star Complement, a joint work with Carlos Luz and Fátima Pacheco, http://enspm16.spm.pt/pt/ 13th EUROPT Workshop on Advances in Continuous Optimization, University of Edinburgh, July 8-10 (presented also as Seminar in May 2015 at Rio de Janeiro, Brazil).

    8. 2014

  8. Star sets, star complements and graphs with convex-qp stability number, with Carlos J. Luz, 4th Combinatorics Day, in honour of Raul Cordovil, May 14, 2014, Department of Mathematics, University of Aveiro and Workshop on Matrices & Operators, with Abraham Berman, June 3-4, 2014, Department of Mathematics, University of Coimbra

    9. 2013

  9. A combinatorial simplex-like approach to graphs with convex-QP stability number using star sets, with Carlos J. Luz, MAT TRIAD, September 16-20, 2013, Herceg-Novi, Montenegro.
  10. Efficient domination through eigenvalues, with Vadim V. Lozin, 26th Conference of the European Chapter on Combinatorial Optimization - ECCO XXVI, May 30 to June 1, 2013, Paris, France.

    11. 2012

  11. The least eigenvalue of graphs with convex-qp stability number,  Latin Ibero-American Spectral Graph Theory Workshop, September 24-28, 2012,  Rio de Janeiro. The LIA-SGT Workshop of CLAIO - Congresso Latino-Iberoamericano de Investigação Operativa, September 24-28, 2012,  Rio de Janeiro, Brazil.
  12. Characterization of Laplacian eigenvalues of caterpillars, with M. Aguieiras de Freitas, Enide A. Martins, Maria Robbiano, Bernardo San Martin, Latin Ibero-American Spectral Graph Theory Workshop,September 24-28, 2012,  Rio de Janeiro. The LIA-SGT Workshop of CLAIO - Congresso Latino-Iberoamericano de Investigação Operativa, September 24-28, 2012,  Rio de Janeiro, Brazil.
  13. Graph Spectra on Combinatorial Optimization, with Nair Abreu and Claudia Justel, Eighth International Colloquium on Graphs and Optimization, Leukerbad, Switzerland, August 13-17 (a similar talk was also presented in the 25th European Conference on Operational Resarch, Vilnius, Lithuania, July 8-11).
  14. Upper bounds on the size of k-regular induced subgraphs based on graph spectra, with Sofia J. Pinheiro, 25th European Conference on Operational Research, Vilnius, Lithuania, July 8-11.

    15. 2011

  15. Spectral characterization of families of split graphs, with Milica Andjelic, Directions in Matrix Theory,, Universidade de Coimbra, Portugal, July 9-10.

    16. 2009

  16. A spectral upper bound for the order of an induced k-regular subgraph, presented by Peter Rowlinson, 22nd British Combinatorial Conference, University of St Andrews, July 5-10.
  17. Convex quadratic upper bounds on the maximum size k-regular induced subgraphs, 7th EUROPT Workshop "Advances in Continuous Optimization", Remagen, Germany, July 3-4.
  18. Recent results on graphs with convex quadratic stability number, presented by Fatima Pacheco, 23rd European Conference on Operational Research, Bonn, July 5-8.

    19. 2007

  19. Majorantes espectrais para o número de estabilidade de grafos, with Sofia J. Pinheiro, CEOC/CIMA-UE joint meeting on Optimization and Optimal Control, October 12-13, Évora.Resumo (in Portuguese).
  20. Graph eigenvalue techniques for the maximum cardinality k-regular induced subgraph problem, with Sofia J. Pinheiro, Optimization 2007 Porto, 22-25 July, 2007. Abstract.
  21. Extensions of the Hoffman bound on the stability number of regular graphs, 6th Slovenian International Conference on Graph Theory Bled, Slovenia, 24-30 June, 2007. Abstract.

    22. 2006

  22. Optimização da diversidade e distribuição de cablagens para a indústria automóvel, with Agostinho Agra, Orestes Cerdeira, Miguel Miranda and Eugénio Rocha. 12º Congresso da APDIO - IO2006, October 8-11, 2006, Lisbon, Portugal Slides (in Portuguese).
  23. Convex quadratic programming techniques on graphs, 21st European Conference on Operational Research, Reykjavik, Iceland, July 2-5, 2006.Abstract<
  24. Spectral results on graphs with regularity constraints, with Paula Rama. Aveiro Workshop on Graph Spectra, Aveiro, Portugal, April 10-12, 2006.Abstract

    25. 2005

  25. On the maximum cardinality of k-regular induced subgraphs, INFORMS Annual Meeting, San Francisco, USA, November 13--16, 2005. Abstract; Slides
  26. Optimization of Diversity and Distribution of Cable Configuration for Automobile Industry, with Agostinho Agra, Orestes Cerdeira, and Eugénio Rocha. 17th EURO Mini Conference: Coninuous Optimization in Industry, Pécs, Hugary, June 29 - July 1, 2005 (this talk is identical to the next one, presented in ECCO XVIII at Minsk)
  27. A spanning star forest model for the diversity problem in automobile industry, with Agostinho Agra, Orestes Cerdeira, and Eugénio Rocha. ECCO XVIII, Minsk, Belarus, May 26-28, 2005. Abstract; Slides
  28. Álgebras de Jordan em Optimização Cónica, with Luís A. Vieira, CEOC/CIMA-UE joint meeting on Optimization and Optimal Control, Évora, Portugal, April 22-23. Slides (in Portuguese).

    29. 2004

  29. Eigenvevectors and eigenvalues of graphs with regularity constraints, with Charles Delorme and Paula Rama. Conference on Graph Theory in memory of Claude Berge, Paris, France, July 5-9, 2004. Abstract.
  30. Continuous optimization techniques on graphs. Workshop on Challenges of Continuous Optimization in Theory and Applications, Rhodes, Greece, July 2-3, 2004. Abstract.

    31. 2003

  31. Abordagens analíticas de um problema combinatório de descodificação de imagens, with M. Helena Silva. VI Congreso Galego de Estatística e Investigación de Operacións, November 5-7, 2003, Vigo, Espanha Resumo.
  32. On Laplacian eigenvectors and eigenvalues and almost equitable partitions, with Charles Delorme and Paula Rama. Combinatorics in Oporto, September 12-17, 2003, Porto, Portugal Abstract.
  33. On a subclass of well-covered graphs, with Rommel Barbosa. Thirty-fourth Southestearn International Conference on Combinatorics, Graph Theory, and Computing, March 3-7, 2003, Boca Raton, Florida, USA. Abstract.

    34. 2002

  34. Confirmation results on multiattribute ranking problems, with J. Freire de Sousa. XI CLAIO Latin-Iberian American Congress of Operations Research, Concepción, Chile, October 27-31. Abstract.
  35. A partial order on the set of solutions of a multiattribute ranking problems, with J. Freire de Sousa. 56th Meeting of the European Working Group "Multiple Criteria Decision Aiding", Coimbra, Portugal, October 3-5. Abstract.
  36. Spectral results on graphs with equitable bipartitions, with Paula C. Rama. Fourth Cracow Conference on Graph Theory - Czorsztyn, Poland, September 16-20. Abstract.
  37. Polynomial-time recognition of graphs with convex-QP stability number in particular hereditary graph classes. Fourth Cracow Conference on Graph Theory - Czorsztyn, Poland, September 16-20. Abstract.
  38. Produtos lexicográficos e cartesianos de grafos: algumas propriedades, with Rommel M. Barbosa. IO'2002, Guimarães, Portugal, March 24-27. Resumo.
  39. Uma abordagem combinatória de um problema de descodificação de imagens, with M. Helena Silva. IO'2002, Guimarães, Portugal, March 24-27. Resumo.
  40. Resultados espectrais em grafos regulares estáveis, with Paula C. Rama. IO'2002, Guimarães, Portugal, March 24-27. Resumo.

    41. 2001

  41. Regular Graphs and Equitable Partitions, with Paula C. Rama. Optimization'2001, Aveiro, Portugal, July 23-25.
  42. On regular-stable graphs, with Rommel M. Barbosa. Optimization'2001, Aveiro, Portugal, July 23-25.

    43. 2000

  43. The class of graphs with convex quadratic stability number, with Carlos J. Luz. 17th Eropean Conference on Operational Research, Budapest, Hugary, July 16-19.
  44. Álgebras de Jordan em Programação Semidefinida, with Luís A. Vieira. IO'2000, Setúbal, Portugal, April 16-19.
  45. Emparelhamentos em Grafos e Aplicações, with Ilídia M. Coelho. IO'2000, Setúbal, Portugal, April 16-19.
  46. Técnicas analíticas em optimização combinatória. IO'2000, Setúbal, Portugal, April 16-19.

    47. 1999

  47. Convex quadratic programming approach to the maximum matching problem. Global Optimization 99, Firenze, Italy, September 28 - October 2.

    48. 1998

  48. Armazenamento e circulação óptima de equipamentos, with F. M. Marques e C. C. Passos. IO'98, Faro, Portugal, November 29 - December 2.
  49. Propriedades de autoconcordância e método de Newton enfraquecido, with Paula C. Rama. IO'98, Faro, Portugal, November 29 - December 2.
  50. Caracterização e análise de barreiras autoconcordantes, with Luís A. Vieira. IO'98, Faro, Portugal, November 29 - December 2.
  51. A Class of graphs with polynomial-time computable stability number, with Carlos J. Luz. Optimization'98, Coimbra, Portugal, July 20-22.

    52. 1997

  52. A reduced recursion for computing Erlang-B function derivatives, with J. Sá Esteves and J. Craveirinha. 15th International Teletraffic Congress, Washington, D.C., USA, June 23-27.

    53. 1996

  53. Bicriteria allocation problems for loss systems with independent links, with J. Sá Esteves and J. Craveirinha. IFORS'96, Vancouver, Canada, July 8-12.
  54. A parallel implementation of of the generalized simplex method, with T. Hultberg and J. Gondzio. IFORS'96, Vancouver, Canada, July 8-12.
  55. Cálculo numérico das derivadas de ordem arbitrária da função de Erlang-B, with J. Sá Esteves and J. Craveirinha. IO'96, Aveiro, Portugal, April 1-3.
  56. Uma implementação paralela do método simplex generalizado, with T. Hultberg and J. Gondzio. IO'96, Aveiro, Portugal, April 1-3.

    57. 1995

  57. A new upper bound on the independence number of a graph, with Carlos J. Luz. Optimization'95, Braga, Portugal, July 17-19.
  58. A generalization of th Hoffman-Lovasz upper bound on the independence number of a regular graph, with Carlos J. Luz. APMOD'95, London, UK, April 3-5.
  59. A Newton-Raphson approach to a server allocation problem for Erlang loss systems, with J. Sá Esteves and J. Craveirinha. APMOD'95, London, UK, April 3-5.

    60. 1994

  60. A bicriteria resource allocation approach for an Erlang-B teletraffic system, with J. Sá Esteves and J. Craveirinha. XIth International Conference on Multiple Criteria Decision Making, Coimbra, Portugal, August 1-6.
  61. Aplicação da Programação Linear a um modelo de distribuição de serviço, with Tim H. Hultberg. IO'94, Braga, Portugal, March 28-30.
  62. Problemas básicos de alocoção de canais em sistemas de Erlang-B, with J. Sá Esteves and J. Craveirinha. IO'94, Braga, Portugal, March 28-30.

    63. 1992

  63. Efficient frontier scanning in MOLP using a new tool, with João N. Clímaco. 10th International Conference on Multiple Criteria Decision Making, Taipei, Taiwan, July 19-24.
  64. Soluções de norma mínima e de mínimos quadrados em sistemas de equações lineares, with Maia Gomes. IO'92, Évora, Portugal, April 13-15.
  65. Um método para a determinação da medida invariante em certos processos de Markov, with L. Tralhão and J. Craveirinha. IO'92, Évora, Portugal, April 13-15.
  66. Sobre a solução admissível inicial em Programação Linear, with João N. Clímaco. IO'92, Évora, Portugal, April 13-15.

    67. 1991

  67. An adjacent face method based on the generalization of the simplex method, with J. N. Clímaco. 14th International Symposium on Mathematical Programming, Amsterdam, Holland, August 5-9.
  68. A face adjacent method based on the generalization of the Simplex Method versus the vertex adjacent methods, with J. N. Clímaco. Workshop on Large-Scale Optimization, Coimbra, Portugal, July 29-31.
  69. A new linear optimization approach based on the generalization of the Simplex Method, with J. N. Clímaco. International Conference on Industrial and Applied Mathematics, Washington, D.C., USA, July 8-12.
  70. A generalized version of the Simplex Method, with J. N. Clímaco. APMOD'91, London, UK.

    71. 1990

  71. Analysis and resolution of fractional programming problems: an approach distinct from the ones based on Dinkelbach's algorithm, with João N. Clímaco. AIRO'90, Sorrento, Italy, October 3-5.

    72. 1988

  72. Dualidade em Programação Linear Fraccionária. IO'89, Lisboa, Portugal, December 18-20.
  73. Software implementation of linear fractional programming methods: a new bicriteria approach versus classical algorithms, with João N. Clímaco. 27th Meeting of the European Working Group on Multiple Criteria Decison Aid, Mons, Belgique, March 24-25.

    74. 1986

  74. Análise de uma aplicação da programação em lógica ao ensino assistido por computador, with Pedro M. Vilarinho. EPIA'86, Lisboa, Portugal, October 8-10.