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Towards Copeland Optimization in Combinatorial Problems

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Integration of Constraint Programming, Artificial Intelligence, and Operations Research (CPAIOR 2022)

Abstract

Traditional approaches to fairness in operations research and social choice, such as the egalitarian/Rawlsian, the utilitarian or the proportional-fair rule implicitly assume that the voters’ utility functions are – to a certain degree – comparable. Otherwise, statements such as “maximize the worst-off voter’s utility” or “maximize the sum of utilities” are void. But what if the different valuations should truly not be compared or converted into each other? Voting theory only relies on ordinal information and can help to provide democratic rules to define winning solutions. Copeland’s method is a well-known generalization of the Condorcet criterion in social choice theory and asks for an outcome that has the best ratio of pairwise majority duel wins to losses. If we simply ask for a feasible solution to a combinatorial problem that maximizes the Copeland score, we are at risk to encounter intractability (due to having to explore all solutions) or suffer from (the lack of) irrelevant alternatives. We present first results from optimizing for a Copeland winner to a constraint problem formulated in MiniZinc in a local search fashion based on a changing solution pool. We investigate the effects of diversity constraints on the quality of the estimated Copeland score as well as the gap between the best reported Copeland scores to the actual Copeland scores.

This research has been sponsored by DAAD Research Internships in Science and Engineering (RISE).

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Notes

  1. 1.

    Our implementation indeed uses integer variables for utilities that need to be maximized but nothing prohibits more general “is-better” predicates.

  2. 2.

    Source code: https://github.com/s1db/Local-Search-Copeland-Method.

References

  1. Bertsimas, D., Farias, V.F., Trichakis, N.: The price of fairness. Oper. Res. 59(1), 17–31 (2011)

    Article  MathSciNet  MATH  Google Scholar 

  2. Brandt, F., Conitzer, V., Endriss, U., Lang, J., Procaccia, A.D.: Handbook of Computational Social Choice. Cambridge University Press, Cambridge (2016)

    Book  MATH  Google Scholar 

  3. de Carvalho, V.R., Sichman, J.S.: Applying copeland voting to design an agent-based hyper-heuristic. In: Proceedings of the 16th Conference on Autonomous Agents and Multiagent Systems, pp. 972–980 (2017)

    Google Scholar 

  4. Chen, V.X., Hooker, J.: Combining leximax fairness and efficiency in a mathematical programming model. Eur. J. Oper. Res. 299(1), 235–248 (2022)

    Article  MathSciNet  MATH  Google Scholar 

  5. Copeland, A.H.: A reasonable social welfare function. Technical report, mimeo. University of Michigan (1951)

    Google Scholar 

  6. Cornelio, C., Pini, M.S., Rossi, F., Venable, K.B.: Multi-agent soft constraint aggregation via sequential voting: theoretical and experimental results. Auton. Agent. Multi-Agent Syst. 33(1), 159–191 (2019). https://doi.org/10.1007/s10458-018-09400-y

    Article  Google Scholar 

  7. Dalla Pozza, G., Rossi, F., Venable, K.B.: Multi-agent soft constraint aggregation: a sequential approach. In: Proceedings 3rd International Conference Agents and Artificial Intelligence ICAART’11, vol. 11 (2010)

    Google Scholar 

  8. Ehrgott, M.: Multicriteria Optimization, vol. 491. Springer Science & Business Media, Heidelberg (2005)

    MATH  Google Scholar 

  9. Fioretto, F., Yeoh, W., Pontelli, E., Ma, Y., Ranade, S.J.: A distributed constraint optimization (DCOP) approach to the economic dispatch with demand response. In: Proceedings 16th International Conference Autonomous Agents and Multiagent Systems (AAMAS 2017), pp. 999–1007. International Foundation for Autonomous Agents and Multiagent Systems (2017)

    Google Scholar 

  10. Frisch, A.M., Harvey, W., Jefferson, C., Martínez-Hernández, B., Miguel, I.: Essence: a constraint language for specifying combinatorial problems. Constraints 13(3), 268–306 (2008). https://doi.org/10.1007/s10601-008-9047-y

    Article  MathSciNet  MATH  Google Scholar 

  11. Gadducci, F., Hölzl, M., Monreale, G.V., Wirsing, M.: Soft constraints for lexicographic orders. In: Castro, F., Gelbukh, A., González, M. (eds.) MICAI 2013. LNCS (LNAI), vol. 8265, pp. 68–79. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-45114-0_6

    Chapter  Google Scholar 

  12. van Hentenryck, P.: The OPL Optimization Programming Language. MIT Press, Cambridge (1999)

    Google Scholar 

  13. Ingmar, L., de la Banda, M.G., Stuckey, P.J., Tack, G.: Modelling diversity of solutions. In: Proceedings of the AAAI Conference on Artificial Intelligence, vol. 34, pp. 1528–1535 (2020)

    Google Scholar 

  14. Knapp, A., Schiendorfer, A., Reif, W.: Quality over quantity in soft constraints. In: Proceedings 26th International Conference Tools with Artificial Intelligence (ICTAI 2014), pp. 453–460 (2014)

    Google Scholar 

  15. McFadden, D., et al.: Conditional Logit Analysis of Qualitative Choice Behavior (1973)

    Google Scholar 

  16. Meseguer, P., Rossi, F., Schiex, T.: Soft constraints. In: Rossi, F., van Beek, P., Walsh, T. (eds.) Handbook of Constraint Programming, chap. 9. Elsevier (2006)

    Google Scholar 

  17. Moulin, H.: Fair Division and Collective Welfare. MIT press, Cambridge (2004)

    Google Scholar 

  18. Nethercote, N., Stuckey, P.J., Becket, R., Brand, S., Duck, G.J., Tack, G.: MiniZinc: towards a standard CP modelling language. In: Bessière, C. (ed.) CP 2007. LNCS, vol. 4741, pp. 529–543. Springer, Heidelberg (2007). https://doi.org/10.1007/978-3-540-74970-7_38

    Chapter  Google Scholar 

  19. Nicosia, G., Pacifici, A., Pferschy, U.: Price of fairness for allocating a bounded resource. Eur. J. Oper. Res. 257(3), 933–943 (2017)

    Article  MathSciNet  MATH  Google Scholar 

  20. Rossi, F.: Collective decision making: a great opportunity for constraint reasoning. Constraints 19(2), 186–194 (2013). https://doi.org/10.1007/s10601-013-9153-3

    Article  Google Scholar 

  21. Rossi, F., Van Beek, P., Walsh, T.: Handbook of Constraint Programming. Elsevier, Amsterdam (2006)

    MATH  Google Scholar 

  22. Schiendorfer, A., Reif, W.: Reducing bias in preference aggregation for multiagent soft constraint problems. In: Schiex, T., de Givry, S. (eds.) CP 2019. LNCS, vol. 11802, pp. 510–526. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-30048-7_30

    Chapter  Google Scholar 

  23. Schulte, C., Lagerkvist, M.Z., Tack, G.: Gecode: generic constraint development environment. In: INFORMS Annual Meeting (2006)

    Google Scholar 

  24. Sen, A.: Collective Choice and Social Welfare. Harvard University Press, Cambridge (2017)

    Book  MATH  Google Scholar 

  25. Stuckey, P.J.: Lazy clause generation: combining the power of SAT and CP (and MIP?) solving. In: Lodi, A., Milano, M., Toth, P. (eds.) CPAIOR 2010. LNCS, vol. 6140, pp. 5–9. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-13520-0_3

    Chapter  Google Scholar 

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Acknowledgments

We thank Guido Tack and Alexander Knapp for initial discussions that led to the idea of this paper.

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Correspondence to Alexander Schiendorfer .

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Bhavnani, S., Schiendorfer, A. (2022). Towards Copeland Optimization in Combinatorial Problems. In: Schaus, P. (eds) Integration of Constraint Programming, Artificial Intelligence, and Operations Research. CPAIOR 2022. Lecture Notes in Computer Science, vol 13292. Springer, Cham. https://doi.org/10.1007/978-3-031-08011-1_4

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  • DOI: https://doi.org/10.1007/978-3-031-08011-1_4

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