After a hiatus caused by the pandemic, the annual Winter School on Network Optimization will resume with the 10th edition which will take place at the Hotel Londres<https://www.hotelondres.com/en/>, Estoril, from the 5th to the 9th of February 2024. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. . In this edition of the school, the lecturers and subjects to be addressed are: Tolga Bektas (University of Liverpool) - Compact formulations, projections and some Polyhedral results for the vehicle and routing problem. Arie Koster (RWTH Aachen University) - Combinatorial and Network Optimization under Uncertainty; Martine Labbé (Université Libre de Bruxelles) - A selective introduction to bilevel optimization Markus Leitner (Vrije Universiteit Amsterdam) - Mathematical optimization for social network analysis; Ivana Ljubic (ESSEC Business School of Paris) - Interdiction and Blocking Problems The school is part of the activities of the ENOG (European Network Optimization Group). Potential participants are invited to submit their CVs to the address netopt2024@fc.ul.pt no later than the November 15. Further information is available in the webpage (https://netopt2024.campus.ciencias.ulisboa.pt<https://netopt2024.campus.ciencias.ulisboa.pt/>) (still being updated).

The 11th edition which will take place at the Hotel Londres<https://www.hotelondres.com/en/>, Estoril, from the 20th to the 24th of January 2025. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. In this edition of the school, the lecturers and subjects to be addressed are: Claudia Archetti (ESSEC, University of Brescia) - Efficient solution approaches for the inventory routing problem Christina Busing (RWTH Aachen University) - Dealing with uncertainty: robustness in combinatorial optimization Juan-Jose Salazar Gonzalez (Universidad de La Laguna) - Mathematical models for the capacitated vehicle routing problem, and variants Martin Schmidt (Trier University) - A gentle and incomplete introduction to bilevel optimization José Valério de Carvalho (Universidade do Minho) - Arc flow formulations based on dynamic programming The school is part of the activities of the ENOG (European Network Optimization Group). Further information will be available in September by email and in the webpage (https://netopt2025.campus.ciencias.ulisboa.pt<https://netopt2024.campus.ciencias.ulisboa.pt/>) (still being updated).

3 Post-Doc Grants are given by CMAFcIO (a Center of Mathematics and OR) of the University of Lisbon Researchers interested can apply by using the link https://cmafcio.ciencias.ulisboa.pt/fellowships

The 11th edition of the Winter School will take place at the Hotel Londres (https://www.hotelondres.com/en/) , Estoril, from the 20th to the 24th of January 2025. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. In this edition of the school, the lecturers and subjects to be addressed are: Claudia Archetti (University of Brescia) - Efficient solution approaches for the inventory routing problem Christina Busing (RWTH Aachen University) - Dealing with uncertainty: robustness in combinatorial optimization Juan-Jose Salazar Gonzalez (Universidad de La Laguna) - Mathematical models for the capacitated vehicle routing problem, and variants Martin Schmidt (Trier University) - A gentle and incomplete introduction to bilevel optimization José Valério de Carvalho (Universidade do Minho) - Arc flow formulations based on dynamic programming The school is part of the activities of the ENOG (European Network Optimization Group). Potential participants are invited to submit their CVs to the address netopt2025@fc.ul.pt no later than October 31. Further information will be available in the webpage (https://netopt2025.campus.ciencias.ulisboa.pt<https://netopt2025.campus.ciencias.ulisboa.pt/><https://netopt2024.campus.ciencias.ulisboa.pt/>) (still being updated).

Revised message with corrected dates The 12th edition of the Winter School will take place at the Hotel Londres (https://www.hotelondres.com/en/) , Estoril, from the 19th to the 23rd of January 2026. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. In this edition of the school, the lecturers and subjects to be addressed are: Bill Cook - The Traveling Salesman Problem and Computational Discrete Optimization Martine Labbé - (Bi)Linear Bilevel Optimization Problems: models, algorithms and applications Ivana Ljubic - Network Resilience and Vulnerability: Protecting the Critical Infrastructure Giovani Rinaldi - QUBO: exact, heuristic, and quantum methods. Hande Yaman - Covering problems and length bounded connectivity The school is part of the activities of the ENOG (European Network Optimization Group). Potential participants will be invited to submit their CVs to the address netopt2026@fc.ul.pt no later than October 31. Further information will be available in the webpage (to be ready in September).

The 12th edition of the Winter School will take place at the Hotel Londres (https://www.hotelondres.com/en/) , Estoril, from the 19th to the 23rd of January 2026. In the spirit of the previous editions, the main objective of the school is to provide an opportunity for PhD students to get together and attend high level courses in the field of Network Optimization. In this edition of the school, the lecturers and subjects to be addressed are: William Cook - The Traveling Salesman Problem and Computational Discrete Optimization Martine Labbé - (Bi)Linear Bilevel Optimization Problems: models, algorithms and applications Ivana Ljubic - Network Resilience and Vulnerability: Protecting the Critical Infrastructure Giovani Rinaldi - QUBO: exact, heuristic, and quantum methods. Hande Yaman - Covering problems and length bounded connectivity The school is part of the activities of the ENOG (European Network Optimization Group). Potential participants are invited to submit their CVs to the address netopt2026@fc.ul.pt no later than October 15. Further information is available in the webpage (https://netopt2026.campus.ciencias.ulisboa.pt).

Dear Colleagues, This is the first announcement of the ECCO XXXIX - CO 2026 joint Conference on Combinatorial Optimization that will take place on May 14-16, 2026 in Lisbon, Portugal. ECCO (the European Chapter on Combinatorial Optimization<https://en.wikipedia.org/wiki/European_Chapter_on_Combinatorial_Optimization>) is a Working Group of EURO (the Association of European Operational Research Societies<https://www.euro-online.org/web/pages/1/home>) that provides an excellent opportunity to discuss recent and important issues in Combinatorial Optimization and its applications. CO series of biennial symposia, the Combinatorial Optimization Conferences, started in the UK in 1977 with meeting venues alternated between the UK and continental Europe. Keynote speakers: William Cook, University of Waterloo Gabor Galambos, University of Szeged Joerg Kalcsics, University of Edinburgh Sergio Garcia Quiles, University of Edinburgh We invite researchers interested in the following areas to submit an abstract: * theory and applications of combinatorial optimization; * optimal solution methods, approximation algorithms and heuristics for combinatorial optimization problems; * integer programming, global optimization, stochastic integer programming, multi-objective programming, graph theory and network flows; * application domains include, but are not limited to: logistics and supply chain optimization, manufacturing, energy production and distribution, land consolidation, telecommunications, bioinformatics, finance. Abstract submission deadline: March 14 , 2026 More details can be found at https://ecco2026.campus.ciencias.ulisboa.pt/ The Program Committee Chair Luis Gouveia

Dear Colleagues, This is the third announcement of the ECCO XXXIX - CO 2026 joint Conference on Combinatorial Optimization that will take place on May 14-16, 2026 in Lisbon, Portugal. ECCO (the European Chapter on Combinatorial Optimization<https://en.wikipedia.org/wiki/European_Chapter_on_Combinatorial_Optimization>) is a Working Group of EURO (the Association of European Operational Research Societies<https://www.euro-online.org/web/pages/1/home>) that provides an excellent opportunity to discuss recent and important issues in Combinatorial Optimization and its applications. CO series of biennial symposia, the Combinatorial Optimization Conferences, started in the UK in 1977 with meeting venues alternated between the UK and continental Europe. Keynote speakers: William Cook, University of Waterloo Gabor Galambos, University of Szeged Joerg Kalcsics, University of Edinburgh Sergio Garcia Quiles, University of Edinburgh We invite researchers interested in the following areas to submit an abstract: * theory and applications of combinatorial optimization; * optimal solution methods, approximation algorithms and heuristics for combinatorial optimization problems; * integer programming, global optimization, stochastic integer programming, multi-objective programming, graph theory and network flows; * application domains include, but are not limited to: logistics and supply chain optimization, manufacturing, energy production and distribution, land consolidation, telecommunications, bioinformatics, finance. Abstract submission deadline: March 14 , 2026 More details can be found at https://ecco2026.campus.ciencias.ulisboa.pt/ The Program Committee Chair Luis Gouveia