Abstract
We consider two-stage multi-leader-follower games, called multi-leader-follower games with vertical information, where leaders in the first stage and followers in the second stage choose simultaneously an action, but those chosen by any leader are observed by only one “exclusive” follower. This partial unobservability leads to extensive form games that have no proper subgames but may have an infinity of Nash equilibria. So it is not possible to refine using the concept of subgame perfect Nash equilibrium and, moreover, the concept of weak perfect Bayesian equilibrium could be not useful since it does not prescribe limitations on the beliefs out of the equilibrium path. This has motivated the introduction of a selection concept for Nash equilibria based on a specific class of beliefs, called passive beliefs, that each follower has about the actions chosen by the leaders rivals of his own leader. In this paper, we illustrate the effectiveness of this concept and we investigate the existence of such a selection for significant classes of problems satisfying generalized concavity properties and conditions of minimal character on possibly discontinuous data.
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Notes
In general, a weak perfect Bayesian equilibrium [(also called weak sequential equilibrium in Myerson 1991] may fall to be a subgame perfect Nash equilibrium, as emphasized by Mas-Colell et al. (1995) in Example 9.C.5 for finite extensive games. However, this is not our case because of the absence of proper subgames in the multi-leader\follower games.
It is worth mentioning that, differently from what may happen in a general extensive game (González-Díaz and Meléndez-Jiménez 2014), in our specific case the system of beliefs is inferred correctly from Bayes’ rule along the path of the equilibrium in pure strategy. This is a consequence of the fact that, if \( {{\varvec{\sigma }}}=( x_1,\ldots , x_k, {\beta }_{1},\ldots , {\beta }_{k})\) is a pure strategy profile, the unique information set of, for example, follower \(F_i\) that is on the path of \({\varvec{\sigma }}\) is the one that is associated with the action \(x_i\); then the probability of being in that information set given that \( {\varvec{\sigma }}\) has been played is equal to 1.
For a proof, one can follow the same reasoning of Proposition 9.C.1 in Mas-Colell et al. (1995).
For the sake of simplicity we improperly identify the system of beliefs in a sequential equilibrium with passive beliefs: our Definition 4 is independent on how the simultaneous moves of the players are rearranged in the tree representation of the game. So, if we consider the game tree in Fig. 1, our definition of passive beliefs does not distinguish between nodes in an information set of follower \(F_2\) that are reached by two action profiles that differ only on the actions of follower \(F_1\).
That is, if \(\underline{t}_i,\overline{t}_i\in \mathbb {R}\) and \(\underline{t}_i\le \overline{t}_i\) then \(l_i(\mathbf {x},\mathbf {y},\underline{t}_i)\le l_i(\mathbf {x},\mathbf {y},\overline{t}_i)\).
References
Avriel M, Diewert W, Schaible S, Zang I (2010) Generalized concavity. SIAM, Philadelphia
Bar-Isaac H, Caruana G, Cuñat V (2012) Search, design and market structure. Am Econ Rev 102:1140–1160
Cellina A (1969) Approximation of set valued functions and fixed point theorems. Ann Mat Pur Appl 82:17–24
Ceparano M (2015) Nash equilibrium selection in multi-leader multi-follower games with vertical separation. PhD thesis, Università degli Studi di Napoli Federico II
Ceparano M, Quartieri F (2017) Nash equilibrium uniqueness in nice games with isotone best replies. J Math Econ (Forthcoming)
Crémer J, Riordan M (1987) On governing multilateral transactions with bilateral contracts. RAND J Econ 18:436–451
Diewert W (1981) Alternative characterizations of six kinds of quasiconcavity in the nondifferentiable case with applications to nonsmooth programming. In: Schaible S, Ziemba W (eds) Generalized concavity in optimization and economics. Academic Press, New York, pp 51–93
Eguia J, Llorente-Saguer A, Morton R, Nicolò A (2014) Equilibrium selection in sequential games with imperfect information. http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2414500
Fiacco A, Kyparisis J (1986) Convexity and concavity properties of the optimal value function in parametric nonlinear programming. J Optimiz Theory Appl 48:95–126
Fudenberg D, Tirole J (1991a) Game theory. MIT press, Cambridge
Fudenberg D, Tirole J (1991b) Perfect Bayesian equilibrium and sequential equilibrium. J Econ Theory 53:236–260
Gavazza A, Lizzeri A (2009) Transparency and economic policy. Rev Econ Stud 76:1023–1048
Giorgi G, Komlósi S (1992) Dini derivatives in optimization—part II. Decis Econ Finance 15:3–24
González-Díaz J, Meléndez-Jiménez MA (2014) On the notion of perfect Bayesian equilibrium. TOP 22:128–143
Hadjisavvas N, Schaible S (2009) Generalized monotone single valued maps. In: Pardalos P, Floudas C (ed) Encyclopedia of optimization, Springer Science & Business Media, pp 1197–1202
Hart O, Tirole J, Carlton D, Williamson O (1990) Vertical integration and market foreclosure. Brook Pap Econ Act Microecon 1990:205–286
Hobbs B, Metzler C, Pang JS (2000) Strategic gaming analysis for electric power systems: an MPEC approach. IEEE Trans Power Syst 15:638–645
Hu M, Fukushima M (2013) Existence, uniqueness, and computation of robust Nash equilibria in a class of multi-leader-follower games. SIAM J Optim 23:894–916
Hu M, Fukushima M (2015) Multi-leader-follower games: models, methods and applications. J Oper Res Soc Jpn 58:1–23
Kakutani S (1941) A generalization of Brouwer’s fixed point theorem. Duke Math J 8:457–459
Kreps D, Wilson R (1982) Sequential equilibria. Econometrica 50:863–894
Kulkarni A, Shanbhag U (2014) A shared-constraint approach to multi-leader multi-follower games. Set Valued Var Anal 22:691–720
Laffont J, Martimort D (2000) Mechanism design with collusion and correlation. Econometrica 68:309–342
Lignola M, Morgan J (1992) Semi-continuities of marginal functions in a sequential setting. Optimization 24:241–252
Loridan P, Morgan J (1989) A theoretical approximation scheme for Stackelberg problems. J Optimiz Theory App 61:95–110
Mangasarian O (1965) Pseudo-convex functions. SIAM J Control Ser A 3:281–290
Mas-Colell A, Whinston M, Green J (1995) Microeconomic theory. Oxford University Press, New York
McAfee R, Schwartz M (1994) Opportunism in multilateral vertical contracting: nondiscrimination, exclusivity, and uniformity. Am Econ Rev 84:210–230
Morgan J (1989) Constrained well-posed two-level optimization problems. In: Nonsmooth Optimization and Related Topics (Erice, 1988), Ettore Majorana Internat. Sci. Ser. Phys. Sci., vol 43, Plenum, New York, pp 307–325
Morgan J, Scalzo V (2007) Pseudocontinuous functions and existence of Nash equilibria. J Math Econ 43:174–183
Myerson R (1991) Game theory: analysis of conflict. Harvard University press, Cambridge, Massachussetts
Nash J (1950) Equilibrium points in n-person games. Proc Natl Acad Sci USA 36:48–49
O’Brien D, Shaffer G (1992) Vertical control with bilateral contracts. RAND J Econ 23:299–308
Pagnozzi M, Piccolo S (2012) Vertical separation with private contracts. Econ J 122:173–207
Pang J, Fukushima M (2005) Quasi-variational inequalities, generalized Nash equilibria, and multi-leader-follower games. Comput Manag Sci 2:21–56
Rockafellar R (1970) Convex analysis. Princeton University Press, Princeton
Schilling R (2005) Measures, integrals and martingales. Cambridge University Press, Cambridge
Selten R (1965) Spieltheoretische behandlung eines oligopolmodells mit nachfrageträgheit: Zeitschrift für die gesamte Staatswissenschaft 121: 301–324, 667–689
Sherali H (1984) A multiple leader Stackelberg model and analysis. Oper Res 32:390–404
Shimizu K, Ishizuka Y (1985) Optimality conditions and algorithms for parameter design problems with two-level structure. IEEE Trans Autom Control 30:986–993
Shimizu K, Ishizuka Y, Bard J (1997) Nondifferentiable and two-level mathematical programming. Kluwer Academic Publishers, Boston
Topkis D (1978) Minimizing a submodular function on a lattice. Oper Res 26:305–321
Yang Z, Ju Y (2016) Existence and generic stability of cooperative equilibria for multi-leader-multi-follower games. J Global Optim 65:563–573
Yu J, Wang H (2008) An existence theorem for equilibrium points for multi-leader-follower games. Nonlinear Anal Theor 69:1775–1777
Acknowledgements
The authors would like to thank Prof. Marco Pagnozzi for the helpful discussions and two anonymous referees whose comments helped to improve and clarify the manuscript. The first author gratefully acknowledges financial support from POR Campania FSE 2014–2020. The second author gratefully acknowledges financial support from Programma STAR Napoli “Equilibrium with ambiguity”.
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Ceparano, M.C., Morgan, J. Equilibrium selection in multi-leader-follower games with vertical information. TOP 25, 526–543 (2017). https://doi.org/10.1007/s11750-017-0444-5
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DOI: https://doi.org/10.1007/s11750-017-0444-5
Keywords
- Multi-leader-follower game
- Selection of equilibria
- Passive belief
- Discontinuous function
- Fixed point
- Generalized concavity