MAJORITY VOTING RULE AND OLIGARCHIC SOCIAL CHOICE RULES
The Institute of Economics and Social Sciences of
Bilkent University
by
PELİN PASİN
In Partial Fulfilment of the Requirements for the Degree of MASTER OF ARTS
in
THE DEPARTMENT OF ECONOMICS BİLKENT UNIVERSITY
ANKARA October 2001
ii
I certify that I have read this thesis and have found that it is fully adequate, in scope and in quality, as a thesis for the degree of Master of Arts
--- Professor Farhad Husseinov Supervisor
I certify that I have read this thesis and have found that it is fully adequate, in scope and in quality, as a thesis for the degree of Master of Arts
--- Assistant Professor Tarık Kara Examining Committee Member
I certify that I have read this thesis and have found that it is fully adequate, in scope and in quality, as a thesis for the degree of Master of Arts
---
Associate Professor Azer Kerimov Examining Committee Member
Approval of the Institute of Economics and Social Sciences
--- Professor Kürşat Aydoğan Director
iii ABSTRACT
MAJORITY VOTING RULE AND OLIGARCHIC SOCIAL CHOICE RULES
Pelin Pasin
M.A., Department of Economics Supervisor: Farhad Husseinov
October 2001
In the first part of this study majority voting rule for two alternatives and continuum agents is characterized. As in the finite agent case, symmetry among agents, neutrality between alternatives and positive responsiveness characterize majority voting rule. In the second part, the relation between T-monotonicity and the group which acts as the oligarchy in an oligarchic social choice rule, is analyzed. It is shown that the minimal coalition for which the social choice rule is monotonic constitutes the oligarchy.
iv ÖZET
OY ÇOKLUĞU SEÇİM KURALI VE OLİGARŞİK SOSYAL SEÇİM KURALLARI
Pelin Pasin
Yüksek Lisans, İktisat Bölümü Tez yöneticisi: Farhad Husseinov
Ekim 2001
Bu çalışmanın ilk bölümünde, iki alternatif ve kontinuum temsilci için oy çokluğu seçim kuralı karakterize edilmiştir. Sonlu temsilci durumunda olduğu gibi, temsilcilerde simetriklik, alternatifler arasında tarafsızlık ve pozitif cevaplılık oy çokluğu seçim kuralını karakterize eder. İkinci bölümde, T-monotonluk ve oligarşik bir sosyal seçim kuralında oligarşi olarak davranacak grup arasındaki ilişki analiz edilmiştir. Sosyal seçim kuralının monotonluğu sağladığı en küçük grubun oligarşiyi oluşturduğu gösterilmiştir.
v
ACKNOWLEDGMENTS
I am deeply grateful to my supervisor, professor Farhad Husseinov, whose knowledge and efforts throughout my studies have been a major source of support. I am also indebted to Assistant Professor Tarık Kara and Associate Professor Azer Kerimov for accepting to review this material and for their valuable suggestions.
I would like to thank also to my family and my friends, especially Seçil Gergün, for their support and encouragement.
