Invited Talks

    2009

  1. 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.
  2. 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.
  3. A natureza combinatória de muitos problemas práticos, 1as Jornadas de Física e Matemática do ISEC, Coimbra, 14 de Janeiro. Resumo (in Portuguese)

    4. 2008

  4. 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

    5. 2007

  5. 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

    6. 2006

  6. Continuous optimization polynomial-time upper bounds on the stability number of graphs, with Sofia Pinheiro. Iberian Conference in Optimization, Coimbra, 16-18 November. Slides.
  7. 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.

    8. 2002

  8. 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.
  9. Problemas combinatórios em conjuntos parcialmente ordenados. Session on Optimization, organized by Joaquim J. Júdice, Encontro Nacional da SPM, Coimbra, Portugal, February 5-8. Resumo.

    10. 2001

  10. 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.
  11. Extensions of a Motzkin-Straus result on the stability number of graphs. Workshop on MaxClique'01, Klagenfurt, Austria, May 31 - June 3. Abstract.

    12. 2000

  12. 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.
  13. 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.

    14. 1999

  14. 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.
  15. 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.

    16. 1998

  16. 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.
  17. Temas e problemas em combinatória. Session on Operational Research, organized by Joaquim J. Júdice, Encontro Nacional da SPM, Braga, Portugal, February 9-12. Resumo.

    18. 1997

  18. 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.

    19. 1993

  19. 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

    2010

  1. 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 presente at Universidade do Minho, Braga, 19 de Janeiro 2009).

    2. 2009

  2. 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.
  3. Conjuntos parcialmente ordenados, polinómios cromáticos e Sudoku, Colóquio de Matemática, Universidade do Minho, Braga, 19 de Janeiro. Slides (in Portuguese)

    4. 2008

  4. Posets, Matching and Partial Colouring. Seminar at the Department of Mathematics, Faculty of Science, University of Malta, 30 April Abstract.
  5. 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.

    6. 2007

  6. 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.

    7. 2005

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

    8. 2004

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

    10. 2003

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

    11. 2002

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

    12. 2000

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

    14. 1999

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

    15. 1997

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

    16. 1994

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

    17. 1991

  17. 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

    2006

  1. 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

  2. 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).

    3. 2000

  3. 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

    2009

  1. 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.
  2. Convex quadratic upper bounds on the maximum size k-regular induced subgraphs, 7th EUROPT Workshop "Advances in Continuous Optimization", Remagen, Germany, July 3-4.
  3. Recent results on graphs with convex quadratic stability number, presented by Fatima Pacheco, 23rd European Conference on Operational Research, Bonn, July 5-8.

    2007

  4. 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).
  5. Graph eigenvalue techniques for the maximum cardinality k-regular induced subgraph problem, with Sofia J. Pinheiro, Optimization 2007 Porto, 22-25 July, 2007. Abstract.
  6. 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.

    7. 2006

  7. 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).
  8. Convex quadratic programming techniques on graphs, 21st European Conference on Operational Research, Reykjavik, Iceland, July 2-5, 2006.Abstract
  9. Spectral results on graphs with regularity constraints, with Paula Rama. Aveiro Workshop on Graph Spectra, Aveiro, Portugal, April 10-12, 2006.Abstract

    10. 2005

  10. On the maximum cardinality of k-regular induced subgraphs, INFORMS Annual Meeting, San Francisco, USA, November 13--16, 2005. Abstract; Slides
  11. 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).
  12. 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.
  13. 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).

    14. 2004

  14. 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.
  15. Continuous optimization techniques on graphs. Workshop on Challenges of Continuous Optimization in Theory and Applications, Rhodes, Greece, July 2-3, 2004. Abstract.

    16. 2003

  16. 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.
  17. 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.
  18. 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.

    19. 2002

  19. 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.
  20. 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.
  21. Spectral results on graphs with equitable bipartitions, with Paula C. Rama. Fourth Cracow Conference on Graph Theory - Czorsztyn, Poland, September 16-20. Abstract.
  22. 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.
  23. Produtos lexicográficos e cartesianos de grafos: algumas propriedades, with Rommel M. Barbosa. IO'2002, Guimarães, Portugal, March 24-27. Resumo.
  24. Uma abordagem combinatória de um problema de descodificação de imagens, with M. Helena Silva. IO'2002, Guimarães, Portugal, March 24-27. Resumo.
  25. Resultados espectrais em grafos regulares estáveis, with Paula C. Rama. IO'2002, Guimarães, Portugal, March 24-27. Resumo.

    26. 2001

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

    28. 2000

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

    32. 1999

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

    33. 1998

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

    37. 1997

  37. 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.

    38. 1996

  38. Bicriteria allocation problems for loss systems with independent links, with J. Sá Esteves and J. Craveirinha. IFORS'96, Vancouver, Canada, July 8-12.
  39. A parallel implementation of of the generalized simplex method, with T. Hultberg and J. Gondzio. IFORS'96, Vancouver, Canada, July 8-12.
  40. 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.
  41. Uma implementação paralela do método simplex generalizado, with T. Hultberg and J. Gondzio. IO'96, Aveiro, Portugal, April 1-3.

    42. 1995

  42. A new upper bound on the independence number of a graph, with Carlos J. Luz. Optimization'95, Braga, Portugal, July 17-19.
  43. 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.
  44. 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.

    45. 1994

  45. 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.
  46. Aplicação da Programação Linear a um modelo de distribuição de serviço, with Tim H. Hultberg. IO'94, Braga, Portugal, March 28-30.
  47. 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.

    48. 1992

  48. 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.
  49. Soluções de norma mínima e de mínimos quadrados em sistemas de equações lineares, with Maia Gomes. IO'92, Évora, Portugal, April 13-15.
  50. 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.
  51. Sobre a solução admissível inicial em Programação Linear, with João N. Clímaco. IO'92, Évora, Portugal, April 13-15.

    52. 1991

  52. 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.
  53. 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.
  54. 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.
  55. A generalized version of the Simplex Method, with J. N. Clímaco. APMOD'91, London, UK.

    56. 1990

  56. 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.

    57. 1988

  57. Dualidade em Programação Linear Fraccionária. IO'89, Lisboa, Portugal, December 18-20.
  58. 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.

    59. 1986

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