1. *J. Zhang, *L. Silveira, H. Validi, L. Smith, A. Buchanan, I. V. Hicks. Partitioning a graph into low-diameter clusters. To appear in the INFORMS Journal on Computing, 2026. (link) (pdf) (code)
2. *B. Alston, H. Validi, I. V. Hicks. Mixed integer linear optimization formulations for learning optimal binary classification trees. To appear in the INFORMS Journal on Computing, 2026. (link) (pdf) (code)
3. *G. Teodoro, H. Validi. Odd-length exchanges in ABO-only kidney exchange: A feasibility puzzle for the classroom. To appear in the INFORMS Transactions on Education, 2026.
4. *R. Gutierrez, *I. Cardoso, H. Validi. Sport Scheduling to Minimize Travels at the FIFA World Cup 2026. To appear in Optimization Letters, 2026. (link) (app) (code)
5. *P. V. Rocha, H. Validi. A cut-based mixed integer programming formulation for the hop-constrained cheapest path problem. To appear in Optimization Letters, 2026. (link) (pdf) (code) (Runner-up for the Undergraduate Paper Competition at the 2025 IISE OR Division)
6. *B. Burin, H. Validi, B. Lyu, I. V. Hicks. Compact mixed integer programming formulations for the minimum biclique cover problem. Networks, 87(3): 257-265, 2026. (link) (pdf) (code)
7. *R. Fakhimi, H. Validi, I. V. Hicks, T. Terlaky, L. F. Zuluaga. A folding preprocess for the max k-cut problem. Optimization Letters, 19(5): 899-917, 2025. (link) (pdf) (code)
8. *A. Karagoz, *R. Liu, H. Validi. Strengthened MIP formulations for the liver region redesign models of Akshat et al. Optimization Letters, 19(3): 505–525, 2025. (link) (code) (news)
9. *S. Kroger, H. Validi, I. V. Hicks. Maximizing engagement in large-scale social networks. INFORMS Journal on Optimization, 6(3-4):196-213, 2024. (link) (code) (Runner-up for the 2025 INFORMS Best Paper Award in the Telecommunication and Network Analytics section)
10. *F. Khoshbakhtian, H. Validi, M. Ventresca, D. Aleman. Optimal design of vaccination policies: A case study for Newfoundland and Labrador. Operations Research Letters, 55: 107140, 2024. (link) (pdf) (code)
11. *S. Kroger, H. Validi, I. V. Hicks. A polytime preprocess algorithm for the maximum independent set problem. Optimization Letters, 18(2): 651-661, 2024. (link) (pdf) (code)
12. *J. Zhang, H. Validi, A. Buchanan, I. V. Hicks. Linear-size formulations for connected planar graph partitioning and political districting. Optimization Letters, 18(1): 19-31, 2024. (link) (pdf) (code)
13. *R. Cacao, *L. Cortez, *J. Forner, H. Validi, I. R. de Farias, I. V. Hicks. The set partitioning problem in a quantum context. Optimization Letters, 18(1): 1-17, 2024. (link) (pdf) (code)
14. *R. Fakhimi, H. Validi, I. V. Hicks, T. Terlaky, L. F. Zuluaga. On relaxations of the max k-cut problem formulations. Operations Research Letters, 51.5: 521-527, 2023. (link) (pdf) (code)
15. H. Validi, A. Buchanan. Political districting to minimize cut edges. Mathematical Programming Computation, 14: 623-672, 2022. (link) (pdf) (code)
16. H. Validi, A. Buchanan, E. Lykhovyd. Imposing contiguity constraints in political districting models. Operations Research, 70(2): 867-892, 2022. (link) (pdf) (code) (slides) (video) (poster) (news) (Winner of the 2021 INFORMS Computing Society Harvey J. Greenberg Research Award)
17. H. Validi, A. Buchanan. The optimal design of low-latency virtual backbones. INFORMS Journal on Computing, 32(4): 952-967, 2020. (link) (pdf) (code) (slides) (video)
18. H. Validi, A. Buchanan. A note on "A linear-size zero-one programming model for the minimum spanning tree problem in planar graphs". Networks, 73(1): 135-142, 2019. (link) (pdf) (slides) (poster)
1. H. Validi, R. Gutierrez, I. Cardoso. Cutting Travel and Jet Lag in the 2026 World Cup Group Stage: What Smarter Scheduling Can Deliver. To appear in ORMS Today, June 2026. (link)
2. H. Validi, A. Buchanan, E. Lykhovyd. Imposing contiguity constraints in political districting models. INFORMS Computing Society Newsletter, Pages 16-22, January 2025.
3. R. Fakhimi, H. Validi. Quantum Approximate Optimization Algorithm (QAOA). Encyclopedia of Optimization, Pages 1-7, 2020. (link) (pdf)
Imposing Connectivity in Network Design Problems, June 2020. (link) (Winner of the 2023 INFORMS Best Dissertation Award in the Telecommunication and Network Analytics section)
1. A. Harkness, H. Validi, *R. Fakhimi, I. V. Hicks, T. Terlaky, L. F. Zuluaga. Characterizing QUBO reformulations of the max-k-cut problem for quantum computing. Major revision submitted to the INFORMS Journal on Computing, April 2026. (link) (code)
2. *T. Barbosa, H. Validi. Polytime procedures for conflict inequalities, elimination, and fixing. Major revision at INFORMS Journal on Computing, May 2026.
3. *S. Kroger, H. Validi, I. V. Hicks, T. Perini. Bounding the number and the diameter of optimal compact Black-majority districts. Major revision at INFORMS Journal on Computing, June 2026. (link) (code)