WG 2019,
49nd International Workshop on Graph Theoretic Concepts in Computer
Science (PC member)

WGT
VIII, Workshop on Graph Theory and its Applications VIII, IMBM
(Chair OC)

WG 2016,
42nd International Workshop on Graph Theoretic Concepts in Computer
Science (Chair OC and PC member)

WGT I-II-III-IV-V-VI, Workshop on Graph Theory and its Applications,
Istanbul (Chair OC).

SIROCCO 2010, Structural Information and Communication Complexity,
Şirince, Turkey (Chair OC and PC)

- ''
*The Nobel Prize in Economic Sciences 2012 and Matching Theory*'', Keynote Lecture

at the 9th International Conference on Operations Research and Enterprise Systems, ICORES 2020, Malta, 22-24 February, 2020.

- The 32nd Conference of the European Chapter on Combinatorial Optimization, ECCO XXXII, The Defensive Domination Problem, May 30 - June 1, 2019, Malta.
- IMBM Discrete Mathematics Days, 2012 Nobel Prize in Economics and Matching Theory, May 4-5, 2019, Istanbul Center for Mathematical Sciences Center, IMBM, Turkey.
- 50th Southeastern International Conference on Combinatorics, Graph Theory & Computing, Advances on Equimatchable Graphs, (Special Session "Structured Families of Graphs and Orders: Mathematical and Algorithmic Aspects") March 4-8, 2019, Boca Raton, FL, USA.

- Workshop on Graph Theory and its Applications VIII, The Defensive Domination Problem, November 2018, Istanbul Center for Mathematical Sciences Center, IMBM, Turkey.
- SIAM Conference on Discrete Mathematics, Minisymposium speaker, The selective coloring problem, June 4-8, 2018, Denver, CO, USA.
- Princeton Discrete Mathematics Seminars, Invited Speaker, Edge-extremal Graphs Under Degree and Matching Number Restrictions, March 2018, Princeton University, USA.

__Combinatorial Potlatch 2017, Invited Speaker, Recent Results on Equimatchable Graphs, November 2017 University of Victoria, Canada.__- 17th Haifa Workshop on Interdisciplinary Applications of Graphs - CRI, Edge extremal Graphs Under Degree and Matching Number Restrictions, June 2017, Haifa, Ceaseria Research Institute, Israel.

- University of Primorska, Invited speaker, Characterization and Recognition of Stable Equimatchable Graphs December 2016, Koper, Slovenia.
- Workshop on Graph Theory and its Applications VI, Co-organizer, Istanbul Center for Mathematical Sciences Center, IMBM, Turkey.
- International Colloquium on Graphs and Optimization GO X, On two extensions of equimatchable Graphs, July 2016, Rigi Kaltbad, Switzerland.
- 3rd Istanbul Design Theory, Graph Theory and Combinatorics Conference, Extensions of Equimatchable Graphs, June 2016, Istanbul, Turkey.
- The Caesarea Rothschild Institute, University of Haifa, Invited speaker, Recent Results on Equimatchable Graphs, January 2016, Haifa, Israel.

- Gebze Teknik Universitesi, Invited speaker, Minimum Maximal Matching and Equimatchable Graphs, December 2015, Kocaeli, Turkey.
- Koc University, Invited speaker, Minimum Maximal Matching and Equimatchable Graphs, December 2015, Istanbul, Turkey.
- John Gimbel's Birthday Conference, Defective Ramsey Numbers, Prague, August 2015.
- Algorithmic Graph Theory on the Adriatic Coast, AGTAC, Equimatchable Graphs are C_2k+1-free for k>= 4, June 16-19, 2015, Koper, Slovenia.
- 13th Cologne-Twente Workshop on Graphs and Combinatorial Optimization, CTW 2015, On the Minimum and Maximum Selective Graph Coloring Problems, May 26-28, 2015, Istanbul, Turkey.

- International Colloquium on Graphs and Optimization, GO IX, Edge intersecting and non-splitting paths in a grid -Part II :One Bend ENPG, Sirmione, Italy.
- Dagstuhl Seminar 14071 : Graph Modification Problems (by invitation only), Convexity in Graphs, Dagstuhl, Germany. Dagstuhl Reports, Volume 4, Issue 2, Page 44, 2014, available online at DOI: 10.4230/DagRep.4.2.38
- The 28th Ljubljiana-Leoben Graph Theory Seminar, Minimum Maximal Matching: old problem, new challenges, invited speaker, Koper, Slovenia.

- Institute of Industrial Engineering & YAEM 2013, Tabu Search Algorithms for Selective Coloring Problem, Istanbul, Turkey.
- CanaDAM, 4th Canadian Discrete and Algorithmic Mathematics Conference, Defective Ramsey Numbers, St John's, Canada.

- 2nd Istanbul Design Theory, Graph Theory and Combinatorics Conference, Defective Ramsey Numbers, Koc University, Istanbul, Turkey.
- 7th Slovenian International Conference on Graph Theory, Defective Ramsey Numbers, Bled, Slovenia.
- Dagstuhl Seminar 11182 : Exploiting graph structure to cope with hard problems (by invitation only), A Survey on Polar graphs, Dagstuhl, Germany Dagstuhl, Reports, Volume 1, Issue 5, 2011, available online at DOI: 10.4230/DagRep.1.5.29

- International Colloquium on Graphs and Optimization, GO VII, Polar graphs, Ovronnaz, Switzerland.
- YAEM 2010, En küçük maksimal eşleme, uygulamalar ve zorluk, Sabancı University, Turkey.
- SIROCCO 2010, Local organization committee chair, Nesin Matematik Köyü, Şirince, Turkey.

- NoNA Spring School on Algorithms, invited lecturer, Some generalized coloring problems, Istanbul.
- Bergen University, invited speaker, Polar graphs, Bergen.
- Sabancı University, Engineering Faculty, invited speaker, Algorithmic Graph Theory and its Applications, Istanbul.

- Bilkent University, IE, Minimum Maximal Matching - Applications and Hardness, invited speaker, Ankara, October 16.
- Graph Theory 2008, (Carsten Thomassen's 60th birthday), Generalized Colorings with applications to some problems in robotics, Sandbjerg Manor, Denmark, August 17-24.
- TAMC'08, Theory and Applications of Models of Computation, Minimum Maximal Matching is NP-hard in regular bipartite graphs, Xi'an, China.
- Koç University, Engineering Faculty, invited speaker, Graph coloring problems and their applications, Istanbul.
- 3ème Cycle Romand de Recherche Opérationnelle, invited lecturer, Minimum Maximal Matching; applications and NP-hardness, Zinal, Switzerland
- Bosphorus University, Computers Sciences, invited speaker, Generalized colorings in line graphs, Istanbul.

- International Colloquium on Graphs and Optimization, GO VI, Covering graphs with cliques and independent sets, Lugano, Switzerland.
- CanaDAM, 1st Canadian Discrete and Algorithmic Mathematics Conference, Covering graphs with cliques and independent sets, Banf, Canada.
- Bosphorus University, IE, invited speaker, Algorithmic graph theory and its applications, Istanbul, Turkey.

- AGAPE I, Generalized vertex coloring problems and their application to permutation graphs, Paris, France.
- Koç University, invited speaker, Generalized vertex coloring problems and their application to permutation graphs, Istanbul, Turkey.
- International Colloquium on Graphs and Optimization, GO V, Polar cographs, Leukerbad, Switzerland
- Sixth Czech-Slovak International Symposium on Combinatorics, Graph Theory, Algorithms and Applications, Polar cographs, Prag, Czech Republic.
- Congrès ROADEF 2006, On the approximation of Min Split-coloring and Min Cocoloring, Lille, France.

- The Fifth ALIO/EURO Conference on Combinatorial Optimization, Split-coloring permutation graphs, Paris, France.
- 2nd Brazilian Symposium on Graphs, Algorithms, and Combinatorics, GRACO'2005, (p,k)-coloring line graphs, Angra Dos Reis, Brasil.

- les quatrièmes journées francophones de recherche opérationnelle, FRANCORO IV, Algorithmes d'approximation et algorithmes séquentiels sur les problèmes de (p; k)-coloration, Fribourg, Switzerland.
- Bilkent University, invited speaker, On generalizations of graph coloring problems, Ankara, Turkey.
- EURO Summer Institute - Optimization and Data Mining, Partitioning cographs into cliques and stable sets, Ankara, Turkey.
- Mathématiques Discrètes et Sciences Sociales -EHESS, invited speaker, Problèmes de (p,k)- partitionnement, Paris, France.

- ROADEF Ecole d'Automne, On Split Coloring Problems, Tours, France.
- First Joint Operations Research Days, IBM Research-The Swiss Operations Research Society, On Split Coloring Problems, Lausanne, Switzerland.
- EURO-INFORMS, Approximation preserving reductions among set covering and vertex covering hierarchies via differential approximation ratio, Istanbul, Turkey.