- Member of the Organizing Committee of the International Workshop “Equilibrium Problems and Variational Models”, Taormina, December 3-5, 1998;
- Member of the Organizing Committee of the International School of Mathematics “G. Stampacchia” 32nd Workshop “Equilibrium Problems and Variational Models”, Erice, June 23 ” July 2, 2000;
- Member of the Organizing Committee of the First Joint Meeting AMS-UMI Special Sessions: “Nonlinear Elliptic and Parabolic Equations and Systems” and “Variational Analysis and Applications”, Pisa, June 12-16, 2002;
- Member of the Organizing Committee of the International Conference on “Variational Analysis and Applications”, Erice, June 20-30, 2003;
- Organizer of the Minisymposium “Equilibrium Problems and Variational Models” during the 5th International Congress on Industrial and Applied Mathematics, Sydney, July 7-11, 2003;
- Member of the Organizing Committee of the Workshop on “Equazioni a Derivate Parziali: Aspetti Metodologici, Modellistica, Applicazioni”, Ragusa Ibla, June 29 – July 2, 2005;
- Member of the Organizing Committee of the International School of Mathematics “G. Stampacchia” 44th Workshop on “Variational Analysis and Partial Differential Equations”, Erice, July 5-14, 2006;
- Co-organizer of the Workshop “Complex Networks – Equilibrium and Vulnerability Analysis with Applications”, Catania, March 10-12, 2008, together with Professor Anna Nagurney;
- Member of the Organizing Committee of the International School of Mathematics “G. Stampacchia” 51st Workshop on “Variational Analysis and Applications”, Erice, May 9-17, 2009;
- Organizer of the session Variational Inequalities and Applications to Economic Market Models, XXIV EURO Conference, Lisbon, July 11-14, 2010;
- Member of the Organizing Committee of the Fifth China-Italy Colloquium on Applied Mathematics CICAM5, Acireale (CT), September 27-30, 2010;
- Co-organizer, together with Dr. Laura Scrimali, of the session “Variational Inequality Problems and Equilibrium Problems”, XLI Conferenza Annuale AIRO, Villa San Giovanni, Septembre 7-10, 2010;
- Member of the Organizing Committee of the International School of Mathematics “G. Stampacchia” 58th Workshop “Variational Analysis and Applications”, Erice, May 14-22, 2012;
- Organizer of the Special Session on Variational Analysis and Equilibrium Problems, 9th AIMS Conference su Dynamical Systems, Differential Equations and Applications, Orlando, July 1-5, 2012;
- Organizer of the Special Session on Equilibrium Problems: formulations and methodologies, Mathematical Programming Symposium, Berlin, August 19-24, 2012;
- Co-organizer, together with Sofia Giuffrè, of the Special Session “Optima and Equilibria: Theory and Applications”, AIRO 2012 Conference, Vietri sul Mare, September 4-7, 2012;
- Co-organizer, together with Antonino Maugeri (University of Catania), of the invited session “Infinite-dimensional Duality and Applications to Continuous Optimization”, EUROPT 2013, 11th EUROPT Workshop on Advances in Continuous Optimization, Florence, June 26-28, 2013;
- Co-organizer, together with Monica Gabriela Cojocaru (University of Guelph, Canada), of the stream “Recent advances in variational inequalities and equilibrium problems with applications”, EURO-INFORMS Joint International Meeting, Rome, July 1-4, 2013;
- Organizer of the session on “Complementarity and Variational Inequalities” at the ICCOPT 2013 Conference, 4th International Conference on Continuous Optimization, Lisbon, July 27 – August 1, 2013;
- Member of the organizing committeeof the 18th European Conference on Mathematics for Industry – ECMI 2014, Taormina, June 9-13, 2014;
- Organizer of the minisymposium on “Recent Advances on Equilibrium Problems with Applications to Networks”, ECMI 2014, Taormina, June 9-13, 2014;
- Co-organizer, together with Sofia Giuffrè, of a session on “Variational Analysis and Applications to Equilibrium Problems” at the 10th AIMS Conference on Dynamical Systems, Differential Equations and Applications, Madrid, July 7 -11, 2014;
- Organizer of the Special Session “Equilibrium Models: Theoretical and Numer- ical Features”, AIRO 2014 Conference, Como, September 2-5, 2014;
- Organizer of the stream “Recent Advances in Dynamics of Variational Inequalities and Equilibrum Problems”, EURO 2015, Glasgow, July 12-15, 2015;
- Member of the Program Committee of thel 2nd International Conference on Dynamics of Disasters, Kalamata, Greece, June 29 – July 2, 2015;
- Co-director of the International Workshop “Variational Analysis and Applications” (VARANA 2015), Erice, August 28 agosto – September 5, 2015, together with C. De Lellis, A. Maugeri, R.T. Rockafellar, M.Théra;
- Co-organizzatrice della Special Session “Equilibrium Models: Theory and Application Features”, AIRO 2015 Conference, Pisa, 7-10 Settembre 2015, insieme a Laura Scrimali;
- Co-organizer of the workshop “Variational Inequalities, Nash Equilibrium Problems and Applications” (VINEPA), Reggio Calabria, September 24-25, 2015, together with S. Giuffrè and L. Scrimali;
- Organizer of the stream “Recent Advances in Dynamics of Variational Inequalities and Equilibrium Problems”, EURO 2016, Poznań, July 3-6, 2016;
- Co-organizer of the Special Session on “Variational Inequalities, Inverse Problems, and Applications”, 11th AIMS Conference on Dynamical Systems, Differential Equations and Applications, Orlando, July 1-5, 2016, together with Baasansuren Jadamba and Akhtar A. Khan;
- Co-organizer of the workshop “Variational Inequalities, Nash Equilibrium Problems and Applications” (VINEPA), Catania, October 6-7, 2016, together with S. Battiato, G.M. Farinella, S. Giuffrè and L. Scrimali;
- Program Committee Member of the 6th International Conference on Operations Research and Enterprice Systems (ICORES), Porto, February 23-25, 2017;
- Member of the Program Committee of the 3rd International Conference on Dynamics of Disasters, Kalamata, Greece, July 5-9, 2017;
- Member of the Program Committee of the 7th International Conference on Operations Research and Enterprice Systems (ICORES), Funchal, Madeira, January 24-26, 2018;
- Co-organizer of the workshop “Variational Inequalities, Nash Equilibrium Problems and Applications” (VINEPA), Reggio Calabria, March 8-9, 2018, together with S. Battiato, G.M. Farinella, S. Giuffré, G. Lax, L. Scrimali;
- Co-director of the International Workshop “Variational Analysis and Applications” (VARANA 2018), Erice, August 28 – September 5, 2018, together with H. Attouch, G. Buttazzo, A. Maugeri;
- Chair of the Program Committee of the International Conference on Optimization and Decision Science (ODS2018), Taormina, September 10-13, 2018;
- Member of the Program Committee of the 8th International Conference on Operations Research and Enterprice Systems (ICORES), Prague, Czech Republic, February 19-21, 2019;
- Member of the Programme Committee of EURO 2019, Dublin, June 23-26, 2019;
- Member of the Organizing Committee of the Conference “Variational Analysis and Applications to PDE and Economy“, Messina, September 19-20, 2019.
- Member of the Program Committee of the 9th International Conference on Operations Research and Enterprice Systems (ICORES), Valletta, Malta, February 22-24, 2020.
- Member of the Program Committee of ODS2020 – Optimization and Decision Science, Rome, November 19, 2020 (online).
- Member of the Program Committee of ODS2021 – Optimization and Decision Science, Rome, September 14-17, 2021.
- Member of the Program Committee of the 11th International Conference on Operations Research and Enterprice Systems (ICORES), online February 3-5, 2022.
- Co-organizer of the stream Variational Inequalities, Equilibria, Games and Multilevel Optimization, EURO 2022, Espoo, July 3-6, 2022, together with G. Bigi and L. Scrimali.
- Member of the Program Committee of the 12th International Conference on Operations Research and Enterprice Systems (ICORES), Lisboa, February 19-21, 2023.
- Member of the Program Committee of ODS2022 – Optimization and Decision Science, Florence, August 30 – September 2, 2022.
- Member of the Program Committee of ODS2023 – Optimization and Decision Science, Ischia, September 4-7, 2023.
- Member of the Program Committee of the 13th International Conference on Operations Research and Enterprice Systems (ICORES), Roma, February 24-26, 2024.
- Co-organizer of the workshop Variational Inequalities, Nash Equilibrium Problems and Applications (VINEPA 2024), Catania, July 11-12, 2024, together with G. Colajanni, S. Giuffré, F. Raciti and L.R.M. Scrimali.
- Member of the Program Committee of the 14th International Conference on Operations Research and Enterprice Systems (ICORES), Porto, February 23-25, 2025.