Skip to main content
Erschienen in: Decisions in Economics and Finance 2/2018

06.09.2018

Proper strong-Fibonacci games

verfasst von: Flavio Pressacco, Laura Ziani

Erschienen in: Decisions in Economics and Finance | Ausgabe 2/2018

Einloggen, um Zugang zu erhalten

Aktivieren Sie unsere intelligente Suche, um passende Fachinhalte oder Patente zu finden.

search-config
loading …

Abstract

We define proper strong-Fibonacci (PSF) games as the subset of proper homogeneous weighted majority games which admit a Fibonacci representation. This is a homogeneous, type-preserving representation whose ordered sequence of type weights and winning quota is the initial string of Fibonacci numbers of the one-step delayed Fibonacci sequence. We show that for a PSF game, the Fibonacci representation coincides with the natural representation of the game. A characterization of PSF games is given in terms of their profile. This opens the way up to a straightforward formula which gives the number \(\varPsi (t)\) of such games as a function of t, number of non-dummy players’ types. It turns out that the growth rate of \(\varPsi (t)\) is exponential. The main result of our paper is that, for two consecutive t values of the same parity, the ratio \(\varPsi (t+2)/\varPsi (t)\) converges toward the golden ratio \({\varPhi }\).
Fußnoten
1
We can signal that there are a few significant papers adopting, like here, the reverse convention. See for instance Isbell (1959), p. 25.
 
2
Some authors consider weighted games which can be non-proper.
 
3
Here, we use the notation \(\mathbb {N}_0\) to denote the set of all positive integers: \(\mathbb {N}_0=\{1,2,3\ldots \}\), while \(\mathbb {N}=\mathbb {N}_{0}\cup \{0\}\).
 
4
Note that there are non-homogeneous games with a unique minimal integral representation (obviously non-homogeneous). For instance, \((\mathbf{w};q)=(1,1,2,2,3,4;7)\) is a non-homogeneous game. Moreover, this game is constant-sum and, in particular, \(w(\varOmega )=2q-1\). Isbell was the first to provide an example of a non-homogeneous game with two minimal integral representations (Isbell 1959, p. 27).
 
5
More generally, in the NR of a homogeneous game, all players of type \(j=1\) have the same individual weight \(w_1=1\).
 
6
For the sake of simplicity, we denote the profile component \({\varPhi }_j(t,z)={\varPhi }_j\).
 
7
For the sake of simplicity, we denote the profile component \(\varUpsilon _j(t,z,p)=\varUpsilon _j\).
 
8
Note that actually there are now two different coalitions, \(S_1(1)\) and \(S_2(2)\), associated respectively to the two players \(i_1\) and \(i_2\) of type \(j=1\). Such coalitions share the same profile. For this reason, we denote them by the same symbol S(1).
 
9
Also here there are two different coalitions, \(S_1(j^{*})\) and \(S_2(j^{*})\), associated respectively to the two players \(i_{1}^{*}\) and \(i_{2}^{*}\) of type \(j=j^{*}\). Such coalitions share the same profile. For this reason, we denote them by the same symbol \(S(j^{*})\).
 
10
It is in order to make a notational warning: while in Proposition 4, \(j^{\bullet }\) was necessarily a member of the set \(J^{'}\), playing (in the one-to-one correspondence with the minimal winning coalition) the role of the weakest player, in the additional part of Proposition 7, the bullet notation is extended to some players of the set \(J^{''}\), because in some minimal winning coalitions, they get the role of weakest player.
 
11
Here, let us explain the troublesome notation used for T. \(S_1(j^{*})\) is the coalition whose weakest player is the one denoted by \(i^{*}_1\) of type \(j^{*}\) (while \(i^{*}_2\) denotes the other one of the same type). We subtract from such a coalition the player of type \(j^{*}+1\), where the notation \(\{j^{*}+1\}\) denotes not the player with individual label \(j^{*}+1\), but his type index \(j^{*}+1\).
 
12
We can signal that the literature adopts the left-right lexicographic order.
 
13
Despite being a homogeneous representation involving all the first 7 components of the Fibonacci sequence, including the winning quota. See Remark 4.
 
14
This is an example of a game with a veto player; for details, see Sect. 10.
 
15
A fundamental property of SSP is that the players of \(G_m\) preserve their weights in the \(G_{m+1}\).
 
16
We exploit definition 24 to use indexes of \(g_{i}\) coherent with the individual labeling of the incidence matrix. In particular, in these games, the player with individual labeling i has Fibonacci weight \(g_{i-1}\).
 
17
It is easy to check that the two weakest players are both or none in each \(S\in W^{m}\) hence \(i_0=2\) can not be replaced by the smallest final step.
 
18
This notation turns out to be useful for the formal proof.
 
Literatur
Zurück zum Zitat Baron, D.P., Ferejohn, J.A.: Bargaining in legislatures. Am. Political Sci. Rev. 83, 1181–1206 (1989)CrossRef Baron, D.P., Ferejohn, J.A.: Bargaining in legislatures. Am. Political Sci. Rev. 83, 1181–1206 (1989)CrossRef
Zurück zum Zitat Fragnelli, V., Gambarelli, G., Gnocchi, N., Pressacco, F., Ziani, L.: Fibonacci representations of homogeneous weighted majority games. In: Nguyen, N.T., Kowalczyk, R., Mercik, J. (eds.) Transactions on computational collective intelligence XXIII. Lecture Notes in Computer Science, vol. 9760, pp. 162–171. Springer, Berlin (2016)CrossRef Fragnelli, V., Gambarelli, G., Gnocchi, N., Pressacco, F., Ziani, L.: Fibonacci representations of homogeneous weighted majority games. In: Nguyen, N.T., Kowalczyk, R., Mercik, J. (eds.) Transactions on computational collective intelligence XXIII. Lecture Notes in Computer Science, vol. 9760, pp. 162–171. Springer, Berlin (2016)CrossRef
Zurück zum Zitat Freixas, J., Kurz, S.: The golden number and Fibonacci sequences in the design of voting structures. Eur. J. Oper. Res. 226, 246–257 (2013)CrossRef Freixas, J., Kurz, S.: The golden number and Fibonacci sequences in the design of voting structures. Eur. J. Oper. Res. 226, 246–257 (2013)CrossRef
Zurück zum Zitat Freixas, J., Kurz, S.: On minimum integer representations of weighted games. Math. Soc. Sci. 67, 9–22 (2014)CrossRef Freixas, J., Kurz, S.: On minimum integer representations of weighted games. Math. Soc. Sci. 67, 9–22 (2014)CrossRef
Zurück zum Zitat Freixas, J., Molinero, X.: Weighted games without a unique minimal representation in integers. Optim. Methods Softw. 25, 203–215 (2010)CrossRef Freixas, J., Molinero, X.: Weighted games without a unique minimal representation in integers. Optim. Methods Softw. 25, 203–215 (2010)CrossRef
Zurück zum Zitat Freixas, J., Molinero, X., Roura, S.: Complete voting systems with two classes of voters: weightedness and counting. Ann. Oper. Res. 193–1, 273–289 (2012)CrossRef Freixas, J., Molinero, X., Roura, S.: Complete voting systems with two classes of voters: weightedness and counting. Ann. Oper. Res. 193–1, 273–289 (2012)CrossRef
Zurück zum Zitat Gurk, H.M., Isbell, J.R.: Simple Solutions, Contributions to the Theory of Games, Vol. IV, Annals of Mathematics Studies, vol. 40, pp. 247–265. Princeton University Press, Princeton (1959) Gurk, H.M., Isbell, J.R.: Simple Solutions, Contributions to the Theory of Games, Vol. IV, Annals of Mathematics Studies, vol. 40, pp. 247–265. Princeton University Press, Princeton (1959)
Zurück zum Zitat Isbell, R.: On the enumeration of majority games. Math. Tables Aids Comput. 13, 21–28 (1959)CrossRef Isbell, R.: On the enumeration of majority games. Math. Tables Aids Comput. 13, 21–28 (1959)CrossRef
Zurück zum Zitat Kalandrakis, T.: Proposal rights and political power. Am. J. Political Sci. 50–2, 441–448 (2006)CrossRef Kalandrakis, T.: Proposal rights and political power. Am. J. Political Sci. 50–2, 441–448 (2006)CrossRef
Zurück zum Zitat Krohn, I., Sudhölter, P.: Directed and weighted majority games. ZOR - Math. Methods Oper. Res. 42, 189–216 (1995)CrossRef Krohn, I., Sudhölter, P.: Directed and weighted majority games. ZOR - Math. Methods Oper. Res. 42, 189–216 (1995)CrossRef
Zurück zum Zitat Le Breton, M., Montero, M., Zaporozhets, V.: Voting power in the EU council of ministers and fair decision making in distributive politics. Math. Soc. Sci. 63, 159–173 (2012)CrossRef Le Breton, M., Montero, M., Zaporozhets, V.: Voting power in the EU council of ministers and fair decision making in distributive politics. Math. Soc. Sci. 63, 159–173 (2012)CrossRef
Zurück zum Zitat Maschler, M., Peleg, B.: A characterization, existence proof and dimension bounds for the kernel of a game. Pacific J. Math. 18–2, 289–328 (1966)CrossRef Maschler, M., Peleg, B.: A characterization, existence proof and dimension bounds for the kernel of a game. Pacific J. Math. 18–2, 289–328 (1966)CrossRef
Zurück zum Zitat Ostmann, A.: On the minimal representation of homogeneous games. Int. J. Game Theory 16, 69–81 (1987)CrossRef Ostmann, A.: On the minimal representation of homogeneous games. Int. J. Game Theory 16, 69–81 (1987)CrossRef
Zurück zum Zitat Peleg, B.: On weights of constant-sum majority games. SIAM J. Appl. Math. 16–3, 527–532 (1968)CrossRef Peleg, B.: On weights of constant-sum majority games. SIAM J. Appl. Math. 16–3, 527–532 (1968)CrossRef
Zurück zum Zitat Philippou, A., Bergum, G.E., Horadam, A.F.: Fibonacci Numbers and Their Applications, Mathematics and its Applications, vol. 18. Springer, Dordrecht (1986)CrossRef Philippou, A., Bergum, G.E., Horadam, A.F.: Fibonacci Numbers and Their Applications, Mathematics and its Applications, vol. 18. Springer, Dordrecht (1986)CrossRef
Zurück zum Zitat Pressacco, F., Ziani, L.: A Fibonacci approach to weighted majority games. J Game Theory 4, 36–44 (2015) Pressacco, F., Ziani, L.: A Fibonacci approach to weighted majority games. J Game Theory 4, 36–44 (2015)
Zurück zum Zitat Rosenmüller, J.: Weighted majority games and the matrix of homogeneity. Oper. Res. 28, 123–141 (1984) Rosenmüller, J.: Weighted majority games and the matrix of homogeneity. Oper. Res. 28, 123–141 (1984)
Zurück zum Zitat Rosenmüller, J.: Homogeneous games: recursive structure and computation. Math. Oper. Res. 12–2, 309–330 (1987)CrossRef Rosenmüller, J.: Homogeneous games: recursive structure and computation. Math. Oper. Res. 12–2, 309–330 (1987)CrossRef
Zurück zum Zitat Rosenmüller, J., Sudhölter, P.: The nucleolus of homogeneous games with steps. Discrete Appl. Math. 50, 53–76 (1994)CrossRef Rosenmüller, J., Sudhölter, P.: The nucleolus of homogeneous games with steps. Discrete Appl. Math. 50, 53–76 (1994)CrossRef
Zurück zum Zitat Schmeidler, D.: The nucleolus of a characteristic function game. SIAM J. Appl. Math. 17–6, 1163–1170 (1969)CrossRef Schmeidler, D.: The nucleolus of a characteristic function game. SIAM J. Appl. Math. 17–6, 1163–1170 (1969)CrossRef
Zurück zum Zitat Von Neumann, J., Morgenstern, O.: Theory of Games and Economic Behaviour. Princeton University Press, Princeton (1944) Von Neumann, J., Morgenstern, O.: Theory of Games and Economic Behaviour. Princeton University Press, Princeton (1944)
Metadaten
Titel
Proper strong-Fibonacci games
verfasst von
Flavio Pressacco
Laura Ziani
Publikationsdatum
06.09.2018
Verlag
Springer International Publishing
Erschienen in
Decisions in Economics and Finance / Ausgabe 2/2018
Print ISSN: 1593-8883
Elektronische ISSN: 1129-6569
DOI
https://doi.org/10.1007/s10203-018-0212-5

Weitere Artikel der Ausgabe 2/2018

Decisions in Economics and Finance 2/2018 Zur Ausgabe