Abstract
This paper demonstrates the possibility of a symmetric “binary-action mixed-strategy equilibrium” in the nested Tullock contest model (Clark and Riis in Public Choice 87:177–184, 1996; Eur J Polit Econ 14(4):605–625, 1998b) with multiple nonmonotone prizes. In this symmetric equilibrium, every player adopts the same mixed strategy: each exerts zero effort with some probability and a constant positive effort otherwise. This new type of equilibrium can coexist with the pure-strategy equilibria established in the literature; it may exist even when those pure-strategy equilibria do not. The coexisting (mixed and pure-strategy) equilibria may induce different levels of effort supply.

Similar content being viewed by others
Notes
Under current NBA rules, the winning chance of getting the top pick for each of the bottom 3 teams is 14%, and the winning chance goes down to 0.5% for the top team (of the 14 non-playoff teams).
This differs from the semi-pure equilibrium in the literature, in which some players adopt a pure strategy and others a mixed one (see, for example, Chowdhury et al. 2016).
Although we are unable to derive explicit equilibrium solutions when \(N\ge 4\) or \(r\ne 1\), we can verify the existence of the binary-mixed equilibrium and fully characterize the equilibrium when it exists, once explicit values of N and r are given.
See Appendix (Full surplus extraction with nonmonotone prizes) for a complete analysis of a three-player contest model.
This is because in such an SPSE (with nonmonotone prizes), the maximum level of total effort is induced for certain; while any mixed-strategy equilibrium can at most induce the same level of total effort in expectation, as each player does not play a pure strategy in equilibrium.
Fu et al. (2015) study contests with endogenous entry. Applying Dasgupta and Maskin (1986), they establish the existence of a symmetric mixed-strategy equilibrium in which a player pays an entry fee and enters the contest with a probability, and stays out of the contest otherwise.
In such a mixed-strategy equilibrium with two asymmetric players, it is common to see that the strong player adopts a pure strategy (always makes a positive effort) and the weak player plays a mixed strategy (only exerts positive effort with a probability).
In the original model of Clark and Riis (1998b), there are K \((<N)\) prizes, denoted by \(\{V_{1},V_{2},\ldots ,V_{K}\}\), which is equivalent to our N-prize specification with \(V_{K+1}=V_{K+2}=\cdots =V_{N}=0\).
Proposition 1 indicates that positive-effort SPSE can exist under nonmonotone prizes.
See Footnote 6 for a detailed explanation.
We also show that a symmetric mixed-strategy equilibrium in which each player randomizes over three positive effort levels does not exist. The detailed proof is available upon request.
The reasoning behind this result is that bidding \(\varepsilon\) rather than 0 would increase the player’s probability of winning \(V_{2}=0\) and decrease her probability of winning \(V_{3}=1.1\) significantly, which thus lowers her expected payoff in a significant manner.
The two theorems in this section show that in a three-player lottery contest, with nonmonotone prizes, a binary-mixed equilibrium cannot coexist with an SPSE.
Note that superscripts CR and BM stand for the SPSE of Clark and Riis (CR) and the binary-mixed (BM) equilibrium proposed in this paper, respectively.
The reverse is also possible, which depends on the prize structure and the value of the discriminatory power.
Note that when \(V_{N}>\frac{1}{N}\left( \sum \nolimits _{k=1}^{N}V_{k}-Z\right)\) and \(V_{1}>\frac{1}{N-1} \sum _{k=2}^{N}V_{k}\), \(TE^{CR}\) can still be positive.
References
Alcalde J, Dahm M (2010) Rent seeking and rent dissipation: a neutrality result. J Public Econ 94(1–2):1–7
Amegashie JA (2000) Some results on rent-seeking contests with shortlisting. Public Choice 105(3–4):245–253
Barut Y, Kovenock D (1998) The symmetric multiple prize all-pay auction with complete information. Eur J Polit Econ 14(4):627–644
Baye MR, Kovenock D, De Vries CG (1994) The solution to the Tullock rent-seeking game when \(R>2\): Mixed-strategy equilibria and mean dissipation rates. Public Choice 81(3–4):363–380
Brown J (2011) Quitters never win: The (adverse) incentive effects of competing with superstars. J Polit Econ 119(5):982–1013
Chowdhury SM, Lee D, Topolyan I (2016) The Max-Min Group Contest: Weakest-link (Group) All-Pay Auction. South Econ J 83(1):105–125
Clark DJ, Riis C (1996) A multi-winner nested rent-seeking contest. Public Choice 87:177–184
Clark DJ, Riis C (1998) Competition over more than one prize. Am Econ Rev 88(1):276–289
Clark DJ, Riis C (1998) Influence and the discretionary allocation of several prizes. Eur J Polit Econ 14(4):605–625
Ewerhart C (2015) Mixed equilibria in Tullock contests. Econ Theor 60(1):59–71
Ewerhart C (2017) Revenue ranking of optimally biased contests: The case of two players. Econ Lett 157:167–170
Feng X, Lu J (2017) Uniqueness of equilibrium in two-player asymmetric Tullock contests with intermediate discriminatory power. Econ Lett 159:61–64
Fu Q, Jiao Q, Lu J (2015) Contests with endogenous entry. Int J Game Theory 44:387–424
Fu Q, Lu J (2009) The beauty of “bigness”: On optimal design of multi-winner contests. Games Econ Behav 66(1):146–161
Fu Q, Lu J (2012) The optimal multi-stage contest. Econ Theor 51(2):351–382
Fu Q, Wu Z (2020) Disclosure and favoritism in sequential elimination contests. Working Paper
Fu Q, Wu Z, Zhu Y (2020) On equilibrium existence in generalized multi-prize lottery contests. Working paper
Glazer A, Hassin R (1988) Optimal contests. Econ Inq 26(1):133–143
Goodman J (2013) The art of the tank. ESPN The Magazine (Retrieved November 29, 2013)
Lu J, Wang Z (2015) Axiomatizing multi-prize nested lottery contests: A complete and strict ranking perspective. J Econ Behav Org 116:127–141
Moldovanu B, Sela A (2001) The optimal allocation of prizes in contests. Am Econ Rev 91(3):542–558
Schweinzer P, Segev E (2012) The optimal prize structure of symmetric Tullock contests. Public Choice 153(1–2):69–82
Siegel R (2009) All-pay contests. Econometrica 77(1):71–92
Sisak D (2009) Multiple-prize contests-the optimal allocation of prizes. J Econ Surveys 23(1):82–114
Szymanski S, Valletti TM (2005) Incentive effects of second prizes. Eur J Polit Econ 21(2):467–481
Wang Z (2010) The optimal accuracy level in asymmetric contests. B.E. J Theor Econ 10(1)
Yates AJ, Heckelman JC (2001) Rent-setting in multiple winner rent-seeking contests. Eur J Polit Econ 17(4):835–852
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
We are grateful to editor Vijay Krishna, an associate editor, and two anonymous reviewers for their helpful comments and suggestions that significantly improved the quality of the paper. Jingfeng Lu gratefully acknowledges financial support from the MOE of Singapore (Grant No.: R122-000-298-115). Zhewei Wang gratefully acknowledges financial support from NSFC (Grant No.: 71973084), Taishan Scholars Program of Shandong Province, and Shandong University.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lu, J., Wang, Z. & Zhou, L. Nested Tullock contests with nonmonotone prizes. Int J Game Theory 52, 303–332 (2023). https://doi.org/10.1007/s00182-022-00820-5
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00182-022-00820-5