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On manipulability of aggregation procedures by coalitions with the same first-ranked alternative
P. 193-194.
The coalitional manipulability of voting rules for special case of coalition formation is studied by computer experiment. For the considered case, the coalition, upon manipulation, consists of agents with the same alternative on the first place in their orderings. Not necessary all agents of the manipulating coalition should report insincere preferences, i.e. manipulating agents can join others by adjusting the preferences. This makes the coalition formation more flexible, inducing the increase of the Nitzan-Kelly manipulability index by different value for different voting rules. Calculations are made for 3 alternatives for knows aggregation procedures.
Publication based on the results of:
Aleskerov F. T., Ivanov A., Karabekyan D. et al., Procedia Computer Science 2015 No. 55 P. 1250-1257
Aleskerov et al. [1] and [2] estimated the degree of manipulability for the case of multi-valued choice (without using any tie-breaking rule) and for Impartial Culture (IC). In our paper, we address the similar question for the multi-valued choice and for Impartial Anonymous Culture (IAC). We use Nitzan-Kelly's (NK) index to estimate the degree of manipulability, which is calculated ...
Added: December 4, 2015
Aleskerov F. T., Ivanov A., Karabekyan D. et al., , in : Advances in Collective Decision Making: Interdisciplinary Perspectives for the 21st Century. : Springer, 2023. P. 95-111.
We study the degree of individual and coalitional manipulability of q-Paretian social choice rules under Impartial Culture. Manipulability is defined as a situation, when an agent or a coalition, which consists of some agents, misrepresents her/their preferences to obtain a better outcome of the social choice rule. We study a class of q-Paretian social choice rules, which ...
Added: June 1, 2023
Bonkoungou S., Alexander Nesterov, Theoretical Economics 2023 Vol. 18 No. 3 P. 965-991
Manipulability is a threat to the successful design of centralized matching markets. However, in many applications some manipulation is inevitable and the designer wants to compare manipulable mechanisms. We count the number of agents with an incentive to manipulate and rank mechanisms by their level of manipulability. This ranking sheds a new light on practical ...
Added: December 9, 2022
Fuad Aleskerov, Karabekyan D., Ivanov A. et al., , in : Evaluating Voting Systems with Probability Models. : Cham : Springer, 2021. P. 231-249.
Added: April 14, 2021
Ivanov A., Информационные технологии и вычислительные системы 2020 № 2 С. 38-50
We study the algorithms for evaluation of manipulatility of aggregation procedures. We consider 27 known aggregation procedures and generalized scoring rules, when the weights of second or second and third alternatives are different. Both Impartial Culture and Impartial Anonymous Culture are studied. We calculate 6 manipulability indices including well-known Nitzan-Kelly index. We provide asymptotic estimations ...
Added: September 25, 2020
Nesterov A. S., Rospuskova O., Rubtsova S., Social Choice and Welfare 2024 P. 1-30
We study the school choice problem and propose a new criterion for comparing non-strategy-proof mechanisms: robustness to manipulations. Mechanism A is more robust than mechanism B if each student (given any preferences of this student and any profile of schools’ priorities) can potentially access a smaller set of schools via a profitable manipulation under mechanism A than under mechanism B. This criterion strengthens the two ...
Added: March 10, 2024
Nesterov A. S., Минибаев К. Р., Ломакин А. С., Economics Letters 2023
We examine incentive compatibility of various school choice mechanisms as measured by the number of manipulating students. We find that Boston with Skips Mechanism, Secure Boston Mechanism, and Chinese Mechanism may have more manipulating students than Boston Mechanism. Similarly, Taiwan Mechanism with smaller deductions may induce more manipulating students than Taiwan Mechanism with larger deductions. ...
Added: March 10, 2024
Bonkoungou S., Nesterov A. S., Theoretical Economics 2021 No. 16(3) P. 881-909
Dozens of school districts and college admissions systems around the world have reformed their admissions rules in recent years. As the main motivation for these reforms, the policymakers cited the strategic flaws of the rules in place: students had incentives to game the system. However, after the reforms, almost none of the new rules became strategy-proof. We explain ...
Added: September 6, 2021
Veselova Y. A., / Высшая школа экономики. Series EC "Economics". 2012. No. 17/EC/2012.
We consider the problem of manipulability of social choice rules in the impartial anonymous and neutral culture model (IANC) and provide a new theoretical study of the IANC model, which allows us to analytically derive the difference between the Nitzan-Kelly index in the Impartial Culture (IC) and IANC models. We show in which cases this ...
Added: October 9, 2012
Aleskerov F. T., Karabekyan D., Ivanov A. et al., , in : Procedia Computer Science. Vol. 122: 5th International Conference on Information Technology and Quantitative Management, ITQM 2017.: Elsevier, 2017. P. 993-1000.
The coalitional manipulability of 13 majoritarian aggregation schemes (voting rules) is studied by computational experiments. We consider a special case of coalition formation in which all agents of manipulating coalition report the same first-ranked alternative upon manipulation, i.e. a group of agents misrepresents their preferences and they agree that the same alternative will be on ...
Added: July 16, 2018
Puchkin N., Spokoiny V., ESAIM: Probability and Statistics 2020 Vol. 24 P. 69-99
We consider a problem of multiclass classification, where the training sample Sn={(Xi,Yi)}ni=1 is generated from the model ℙ(Y=m|X=x)=ηm(x), 1≤m≤M, and η1(x),…,ηM(x) are unknown α-Holder continuous functions.Given a test point X, our goal is to predict its label. A widely used 𝗄-nearest-neighbors classifier constructs estimates of η1(X),…,ηM(X) and uses a plug-in rule for the prediction. However, it requires a proper choice of the smoothing parameter 𝗄, which may ...
Added: October 30, 2019
Ivanov A., Журнал Новой экономической ассоциации 2022 № 5(57) С. 14-23
Abstract. Manipulation is a phenomenon when an agent or a group of agents misrepresent her/their preferences in the ballots in order to obtain a better outcome of the social choice. It has been proven that there is no not-dictatorial social choice rule which is nonmanipulable. There are two approaches to fi nd the least manipulable ...
Added: January 26, 2024
Aleskerov F. T., Karabekyan D., Sanver M. et al., , in : Модернизация экономики и глобализация: В 3 кн. Кн. 3. Кн. 3.: М. : Издательский дом ГУ-ВШЭ, 2009. P. 577-591.
The problem of the manipulability of known social choice rules in the case of multiple choice is considered. Several concepts of expanded preferences (preferences over the sets of alternatives) are elaborated. As a result of this analysis ordinal and nonordinal methods of preferences expanding are defined. The notions of the degree of manipulability are extended ...
Added: August 20, 2013
Nesterov A. S., Journal of Economic Theory 2017 No. 170 P. 145-168
I consider the problem of allocating N indivisible objects among N agents according to their preferences when transfers are absent and an outside option may exist. I study the tradeoff between fairness and efficiency in the class of strategy-proof mechanisms. The main finding is that for strategy-proof mechanisms the following efficiency and fairness criteria are mutually incompatible: (1) ex-post efficiency and envy-freeness, (2) ordinal efficiency and weak envy-freeness, and (3) ordinal ...
Added: May 30, 2017
Karabekyan D., Журнал Новой экономической ассоциации 2022 № 5(57) С. 24-37
Some distortions are possible in the process of preference aggregation. For example, one voter who is pivotal for some preference profi le may not read instructions properly and accidently submit wrong preference. We study how different voting rules react to these distortions for three, four and fi ve alternatives with computer modelling. One of the ...
Added: January 17, 2023
Ivanov A., , in : Data Analysis and Optimization. In Honor of Boris Mirkin's 80th Birthday. : Springer, 2023. P. 157-168.
Manipulation is a situation when an agent misrepresents his/her preferences to obtain a better result of an aggregation procedure. It was proven in literature, that there is no non-dictatorial aggregation procedure which is non-manipulable. A number of papers studying the degree of manipulability of aggregation procedures have been published since then. Such papers either look ...
Added: January 26, 2024
Nesterov A. S., Минибаев К. Р., Ломакин А. С., Economics Letters 2023
We examine incentive compatibility of various school choice mechanisms as measured by the number of manipulating students. We find that Boston with Skips Mechanism, Secure Boston Mechanism, and Chinese Mechanism may have more manipulating students than Boston Mechanism. Similarly, Taiwan Mechanism with smaller deductions may induce more manipulating students than Taiwan Mechanism with larger deductions. ...
Added: October 6, 2023
Karabekyan D., Yakuba V. I., , in : Proceedings of the 20th International Conference on Group Decision and Negotiation. : Ryerson University, 2020. P. 120-132.
For the two-dimensional Downsian model the degree of manipulability of 16 known aggregation procedures, based on the majority relation, is evaluated using the Nitzan-Kelly index. Extended preferences for multi-valued choices are used to evaluate the fact of manipulation. Individual manipulability of agents is considered, when manipulating agent moves its ideal point over the plane. The ...
Added: September 3, 2020
Bonkoungou S., Nesterov A. S., / National Research University Higher School of Economics. Series WP BRP "Basic research program". 2021. No. 249.
Vulnerability to manipulation is a threat to successful matching market design. However, some manipulation is often inevitable and the mechanism designer wants to compare manipulable mechanisms and pick the best. Real-life examples include reforms in the entry-level medical labor market in the US (1998), school admissions systems in New York (2004), Chicago (2009-2010), Denver (2012), some cities in ...
Added: September 6, 2021
Nesterov A. S., Theoretical Economics 2022 P. 1-28
In this paper we investigate when a series of reforms of school admissions mechanisms are motivated by fairness concerns. Prior to the reforms as well as after, the mechanisms are vulnerable to manipulation and unfair as they may have blocking students who miss schools that they are entitled to. We show that some of these ...
Added: December 5, 2022