Multi Winner Voting With Approval Preferences

Author : Martin Lackner
Publisher : Springer
ISBN 13 : 9783031090158
Total Pages : 0 pages
Book Rating : 4.52/5 ( download)

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Download or read book Multi-Winner Voting with Approval Preferences written by Martin Lackner and published by Springer. This book was released on 2022-11-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental concepts and results to recent advances in computational social choice, this open access book provides a thorough and in-depth look at multi-winner voting based on approval preferences. The main focus is on axiomatic analysis, algorithmic results and several applications that are relevant in artificial intelligence, computer science and elections of any kind. What is the best way to select a set of candidates for a shortlist, for an executive committee, or for product recommendations? Multi-winner voting is the process of selecting a fixed-size set of candidates based on the preferences expressed by the voters. A wide variety of decision processes in settings ranging from politics (parliamentary elections) to the design of modern computer applications (collaborative filtering, dynamic Q&A platforms, diversity in search results, etc.) share the problem of identifying a representative subset of alternatives. The study of multi-winner voting provides the principled analysis of this task. Approval-based committee voting rules (in short: ABC rules) are multi-winner voting rules particularly suitable for practical use. Their usability is founded on the straightforward form in which the voters can express preferences: voters simply have to differentiate between approved and disapproved candidates. Proposals for ABC rules are numerous, some dating back to the late 19th century while others have been introduced only very recently. This book explains and discusses these rules, highlighting their individual strengths and weaknesses. With the help of this book, the reader will be able to choose a suitable ABC voting rule in a principled fashion, participate in, and be up to date with the ongoing research on this topic.

Author : John H Aldrich
Publisher : University of Michigan Press
ISBN 13 : 0472901125
Total Pages : 253 pages
Book Rating : 4.28/5 ( download)

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Download or read book The Many Faces of Strategic Voting written by John H Aldrich and published by University of Michigan Press. This book was released on 2019-02-28 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Voters do not always choose their preferred candidate on election day. Often they cast their ballots to prevent a particular outcome, as when their own preferred candidate has no hope of winning and they want to prevent another, undesirable candidate’s victory; or, they vote to promote a single-party majority in parliamentary systems, when their own candidate is from a party that has no hope of winning. In their thought-provoking book The Many Faces of Strategic Voting, Laura B. Stephenson, John H. Aldrich, and André Blais first provide a conceptual framework for understanding why people vote strategically, and what the differences are between sincere and strategic voting behaviors. Expert contributors then explore the many facets of strategic voting through case studies in Great Britain, Spain, Canada, Japan, Belgium, Germany, Switzerland, and the European Union.

Author : Jean-François Laslier
Publisher : Springer Science & Business Media
ISBN 13 : 364202839X
Total Pages : 482 pages
Book Rating : 4.97/5 ( download)

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Download or read book Handbook on Approval Voting written by Jean-François Laslier and published by Springer Science & Business Media. This book was released on 2010-06-25 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: With approval voting, voters can approve of as many candidates as they want, and the one approved by the most voters wins. This book surveys a wide variety of empirical and theoretical knowledge accumulated from years of studying this method of voting.

Author : Ulle Endriss
Publisher : Lulu.com
ISBN 13 : 1326912097
Total Pages : 424 pages
Book Rating : 4.93/5 ( download)

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Download or read book Trends in Computational Social Choice written by Ulle Endriss and published by Lulu.com. This book was released on 2017-10-26 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational social choice is concerned with the design and analysis of methods for collective decision making. It is a research area that is located at the interface of computer science and economics. The central question studied in computational social choice is that of how best to aggregate the individual points of view of several agents, so as to arrive at a reasonable compromise. Examples include tallying the votes cast in an election, aggregating the professional opinions of several experts, and finding a fair manner of dividing a set of resources amongst the members of a group -- Back cover.

Author : Martin Lackner
Publisher : Springer Nature
ISBN 13 : 3031090160
Total Pages : 127 pages
Book Rating : 4.65/5 ( download)

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Download or read book Multi-Winner Voting with Approval Preferences written by Martin Lackner and published by Springer Nature. This book was released on 2022-11-17 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: From fundamental concepts and results to recent advances in computational social choice, this open access book provides a thorough and in-depth look at multi-winner voting based on approval preferences. The main focus is on axiomatic analysis, algorithmic results and several applications that are relevant in artificial intelligence, computer science and elections of any kind. What is the best way to select a set of candidates for a shortlist, for an executive committee, or for product recommendations? Multi-winner voting is the process of selecting a fixed-size set of candidates based on the preferences expressed by the voters. A wide variety of decision processes in settings ranging from politics (parliamentary elections) to the design of modern computer applications (collaborative filtering, dynamic Q&A platforms, diversity in search results, etc.) share the problem of identifying a representative subset of alternatives. The study of multi-winner voting provides the principled analysis of this task. Approval-based committee voting rules (in short: ABC rules) are multi-winner voting rules particularly suitable for practical use. Their usability is founded on the straightforward form in which the voters can express preferences: voters simply have to differentiate between approved and disapproved candidates. Proposals for ABC rules are numerous, some dating back to the late 19th century while others have been introduced only very recently. This book explains and discusses these rules, highlighting their individual strengths and weaknesses. With the help of this book, the reader will be able to choose a suitable ABC voting rule in a principled fashion, participate in, and be up to date with the ongoing research on this topic.

Author : D. Marc Kilgour
Publisher : Springer Science & Business Media
ISBN 13 : 9048190975
Total Pages : 473 pages
Book Rating : 4.73/5 ( download)

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Download or read book Handbook of Group Decision and Negotiation written by D. Marc Kilgour and published by Springer Science & Business Media. This book was released on 2010-08-02 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publication of the Handbook of Group Decision and Negotiation marks a milestone in the evolution of the group decision and negotiation (GDN) eld. On this occasion, editors Colin Eden and Marc Kilgour asked me to write a brief history of the eld to provide background and context for the volume. They said that I am in a good position to do so: Actively involved in creating the GDN Section and serving as its chair; founding and leading the GDN journal, Group Decision and Negotiation as editor-in-chief, and the book series, “Advances in Group Decision and Negotiation” as editor; and serving as general chair of the GDN annual meetings. I accepted their invitation to write a brief history. In 1989 what is now the Institute for Operations Research and the Management Sciences (INFORMS) established its Section on Group Decision and Negotiation. The journal Group Decision and Negotiation was founded in 1992, published by Springer in cooperation with INFORMS and the GDN Section. In 2003, as an ext- sion of the journal, the Springer book series, “Advances in Group Decision and Negotiation” was inaugurated.

Author : William Poundstone
Publisher : Macmillan
ISBN 13 : 9780809048922
Total Pages : 360 pages
Book Rating : 4.22/5 ( download)

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Download or read book Gaming the Vote written by William Poundstone and published by Macmillan. This book was released on 2009-02-17 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: At least five U.S. presidential elections have been won by the second most popular candidate, because of "spoilers"--Minor candidates who take enough votes away from the most popular candidate to tip the election. The spoiler effect is a consequence of the "impossibility theorem," discovered by Nobel laureate economist Kenneth Arrow, which asserts that voting is fundamentally unfair--and political strategists are exploiting the mathematical faults of the simple majority vote. This book presents a solution to the spoiler problem: a system called range voting, already widely used on the Internet, which is the fairest voting method of all, according to computer studies. Range voting remains controversial, however, and author Poundstone assesses the obstacles confronting any attempt to change the American electoral system.--From publisher description.

Author : Kaczmarczyk, Andrzej
Publisher : Universitätsverlag der TU Berlin
ISBN 13 : 3798332150
Total Pages : 248 pages
Book Rating : 4.57/5 ( download)

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Download or read book Algorithmic aspects of resource allocation and multiwinner voting: theory and experiments written by Kaczmarczyk, Andrzej and published by Universitätsverlag der TU Berlin. This book was released on 2021-12-10 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is concerned with investigating elements of computational social choice in the light of real-world applications. We contribute to a better understanding of the areas of fair allocation and multiwinner voting. For both areas, inspired by real-world scenarios, we propose several new notions and extensions of existing models. Then, we analyze the complexity of answering the computational questions raised by the introduced concepts. To this end, we look through the lens of parameterized complexity. We identify different parameters which describe natural features specific to the computational problems we investigate. Exploiting the parameters, we successfully develop efficient algorithms for spe- cific cases of the studied problems. We complement our analysis by showing which parameters presumably cannot be utilized for seeking efficient algorithms. Thereby, we provide comprehensive pictures of the computational complexity of the studied problems. Specifically, we concentrate on four topics that we present below, grouped by our two areas of interest. For all but one topic, we present experimental studies based on implementations of newly developed algorithms. We first focus on fair allocation of indivisible resources. In this setting, we consider a collection of indivisible resources and a group of agents. Each agent reports its utility evaluation of every resource and the task is to “fairly” allocate the resources such that each resource is allocated to at most one agent. We concentrate on the two following issues regarding this scenario. The social context in fair allocation of indivisible resources. In many fair allocation settings, it is unlikely that every agent knows all other agents. For example, consider a scenario where the agents represent employees of a large corporation. It is highly unlikely that every employee knows every other employee. Motivated by such settings, we come up with a new model of graph envy-freeness by adapting the classical envy-freeness notion to account for social relations of agents modeled as social networks. We show that if the given social network of agents is simple (for example, if it is a directed acyclic graph), then indeed we can sometimes find fair allocations efficiently. However, we contrast tractability results with showing NP-hardness for several cases, including those in which the given social network has a constant degree. Fair allocations among few agents with bounded rationality. Bounded rationality is the idea that humans, due to cognitive limitations, tend to simplify problems that they face. One of its emanations is that human agents usually tend to report simple utilities over the resources that they want to allocate; for example, agents may categorize the available resources only into two groups of desirable and undesirable ones. Applying techniques for solving integer linear programs, we show that exploiting bounded rationality leads to efficient algorithms for finding envy-free and Pareto-efficient allocations, assuming a small number of agents. Further, we demonstrate that our result actually forms a framework that can be applied to a number of different fairness concepts like envy-freeness up to one good or envy-freeness up to any good. This way, we obtain efficient algorithms for a number of fair allocation problems (assuming few agents with bounded rationality). We also empirically show that our technique is applicable in practice. Further, we study multiwinner voting, where we are given a collection of voters and their preferences over a set of candidates. The outcome of a multiwinner voting rule is a group (or a set of groups in case of ties) of candidates that reflect the voters’ preferences best according to some objective. In this context, we investigate the following themes. The robustness of election outcomes. We study how robust outcomes of multiwinner elections are against possible mistakes made by voters. Assuming that each voter casts a ballot in a form of a ranking of candidates, we represent a mistake by a swap of adjacent candidates in a ballot. We find that for rules such as SNTV, k-Approval, and k-Borda, it is computationally easy to find the minimum number of swaps resulting in a change of an outcome. This task is, however, NP-hard for STV and the Chamberlin-Courant rule. We conclude our study of robustness with experimentally studying the average number of random swaps leading to a change of an outcome for several rules. Strategic voting in multiwinner elections. We ask whether a given group of cooperating voters can manipulate an election outcome in a favorable way. We focus on the k-Approval voting rule and we show that the computational complexity of answering the posed question has a rich structure. We spot several cases for which our problem is polynomial-time solvable. However, we also identify NP-hard cases. For several of them, we show how to circumvent the hardness by fixed-parameter tractability. We also present experimental studies indicating that our algorithms are applicable in practice. Diese Arbeit befasst sich mit der Untersuchung von Themen des Forschungsgebiets Computational Social Choice im Lichte realer Anwendungen. Dabei trägt sie zu einem besseren Verständnis der Bereiche der fairen Zuordnung und der Mehrgewinnerwahlen bei. Für beide Konzepte schlagen wir – inspiriert von realen Anwendungen – verschiedene neue Begriffe und Erweiterungen bestehender Modelle vor. Anschließend analysieren wir die Komplexität der Beantwortung von Berechnungsfragen, die durch die eingeführten Konzepte aufgeworfen werden. Dabei fokussieren wir uns auf die parametrisierte Komplexität. Hierzu identifizieren wir verschiedene Parameter, welche natürliche Merkmale der von uns untersuchten Berechnungsprobleme beschreiben. Durch die Nutzung dieser Parameter entwickeln wir erfolgreich effiziente Algorithmen für Spezialfälle der untersuchten Probleme. Wir ergänzen unsere Analyse indem wir zeigen, welche Parameter vermutlich nicht verwendet werden können um effiziente Algorithmen zu finden. Dabei zeichnen wir ein umfassendes Bild der Berechnungskomplexität der untersuchten Probleme. Insbesondere konzentrieren wir uns auf vier Themen, die wir, gruppiert nach unseren beiden Schwerpunkten, unten vorstellen. Für alle Themen bis auf eines präsentieren wir Experimente, die auf Implementierungen der von uns neu entwickelten Algorithmen basieren. Wir konzentrieren uns zunächst auf die faire Zuordnung unteilbarer Ressourcen. Hier betrachten wir eine Menge unteilbarer Ressourcen und eine Gruppe von Agenten. Jeder Agent gibt eine Bewertung des Nutzens jeder Ressource ab und die Aufgabe besteht darin, eine "faire" Zuordnung der Ressourcen zu finden, wobei jede Ressource höchstens einem Agenten zugeordnet werden kann. Innerhalb dieses Bereiches konzentrieren wir uns auf die beiden folgenden Problemstellungen. Der soziale Kontext bei der fairen Zuordnung unteilbarer Ressourcen. In vielen Szenarien, in denen Ressourcen zugeordnet werden sollen, ist es unwahrscheinlich, dass jeder Agent alle anderen kennt. Vorstellbar ist beispielsweise ein Szenario, in dem die Agenten Mitarbeiter eines großen Unternehmens repräsentieren. Es ist höchst unwahrscheinlich, dass jeder Mitarbeiter jeden anderen Mitarbeiter kennt. Motiviert durch solche Szenarien entwickeln wir ein neues Modell der graph-basierten Neidfreiheit. Wir erweitern den klassischen Neidfreiheitsbegriff um die sozialen Beziehungen von Agenten, die durch soziale Netzwerke modelliert werden. Einerseits zeigen wir, dass wenn das soziale Netzwerk der Agenten einfach ist (zum Beispiel, wenn es sich um einen gerichteten azyklischen Graph handelt), in manchen Fällen faire Zuordnungen effizient gefunden werden können. Andererseits stellen wir diesen algorithmisch positiven Ergebnissen mehrere NP-schweren Fällen entgegen. Ein Beispiel für einen solchen Fall sind soziale Netzwerke mit einem konstanten Knotengrad. Faire Zuteilung an wenige Agenten mit begrenzter Rationalität. Begrenzte Rationalität beschreibt die Idee, dass Menschen aufgrund kognitiver Grenzen dazu neigen, Probleme, mit denen sie konfrontiert werden, zu vereinfachen. Eine mögliche Folge dieser Grenzen ist, dass menschliche Agenten in der Regel einfache Bewertungen der gewünschten Ressourcen abgeben; beispielsweise könnten Agenten die verfügbaren Ressourcen nur in zwei Gruppen, erwünschte und unerwünschte Ressourcen, kategorisieren. Durch Anwendung von Techniken zum Lösen von Ganzzahligen Linearen Programmen zeigen wir, dass unter der Annahme einer kleinen Anzahl von Agenten die Ausnutzung begrenzter Rationalität dabei hilft, effiziente Algorithmen zum Finden neidfreier und Pareto-effizienter Zuweisungen zu entwickeln. Weiterhin zeigen wir, dass unser Ergebnis ein allgemeines Verfahren liefert, welches auf eine Reihe verschiedener Fairnesskonzepte angewendet werden kann, wie zum Beispiel Neidfreiheit bis auf ein Gut oder Neidfreiheit bis auf irgendein Gut. Auf diese Weise gewinnen wir effiziente Algorithmen für eine Reihe fairer Zuordnungsprobleme (wenige Agenten mit begrenzter Rationalität vorausgesetzt). Darüber hinaus zeigen wir empirisch, dass unsere Technik in der Praxis anwendbar ist. Weiterhin untersuchen wir Mehrgewinnerwahlen, bei denen uns eine Menge von Wählern sowie ihre Präferenzen über eine Reihe von Kandidaten gegeben sind. Das Ergebnis eines Mehrgewinnerwahlverfahrens ist eine Gruppe (oder eine Menge von Gruppen im Falle eines Unentschiedens) von Kandidaten, welche die Präferenzen der Wähler am besten einem bestimmten Ziel folgend widerspiegeln. In diesem Kontext untersuchen wir die folgenden Themen. Die Robustheit von Wahlergebnissen. Wir untersuchen, wie robust die Ergebnisse von Mehrgewinnerwahlen gegenüber möglicher Fehler der Wähler sind. Unter der Annahme, dass jeder Wähler eine Stimme in Form einer Rangliste von Kandidaten abgibt, modellieren wir einen Fehler als einen Tausch benachbarter Kandidaten in der Rangliste. Wir zeigen, dass für Wahlregeln wie SNTV, k-Approval und k-Borda die minimale Anzahl an Vertauschungen, welche zu einer Ergebnisänderung führt, einfach zu berechnen ist. Für STV und die Chamberlin-Courant-Regel ist diese Aufgabe allerdings NP-schwer. Wir schließen unsere Untersuchung der Robustheit unterschiedlicher Wahlregeln ab mit einer experimentellen Evaluierung der durchschnittlichen Anzahl zufälliger Vertauschungen, die zu einer Änderung des Ergebnisses führen. Strategische Abstimmung bei Wahlen mit mehreren Gewinnern. Wir fragen, ob eine bestimmte Gruppe von kooperierenden Wählern ein Wahlergebnis zu ihren Gunsten manipulieren kann. Dabei konzentrieren wir uns auf die k-Approval-Wahlregel. Wir zeigen, dass die Berechnungskomplexität der besagten Manipulation eine reiche Struktur besitzt. Auf der einen Seite identifizieren wir mehrere Fälle in denen das Problem in Polynomzeit lösbar ist. Auf der anderen Seite identifizieren wir jedoch auch NP-schwere Fälle. Für einige von ihnen zeigen wir, wie die Berechnungsschwere durch parametrisierte Algorithmen umgangen werden kann. Wir präsentieren zudem experimentelle Untersuchungen, welche darauf hindeuten, dass unsere Algorithmen in der Praxis anwendbar sind.

Author : Felix Brandt
Publisher : Cambridge University Press
ISBN 13 : 1107060435
Total Pages : 553 pages
Book Rating : 4.32/5 ( download)

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Download or read book Handbook of Computational Social Choice written by Felix Brandt and published by Cambridge University Press. This book was released on 2016-04-25 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive survey of computational aspects of collective decisions for graduate students, researchers, and professionals in computer science and economics.

Author : Reshef Liu
Publisher : Springer Nature
ISBN 13 : 3031015797
Total Pages : 149 pages
Book Rating : 4.93/5 ( download)

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Download or read book Strategic Voting written by Reshef Liu and published by Springer Nature. This book was released on 2022-05-31 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Social choice theory deals with aggregating the preferences of multiple individuals regarding several available alternatives, a situation colloquially known as voting. There are many different voting rules in use and even more in the literature, owing to the various considerations such an aggregation method should take into account. The analysis of voting scenarios becomes particularly challenging in the presence of strategic voters, that is, voters that misreport their true preferences in an attempt to obtain a more favorable outcome. In a world that is tightly connected by the Internet, where multiple groups with complex incentives make frequent joint decisions, the interest in strategic voting exceeds the scope of political science and is a focus of research in economics, game theory, sociology, mathematics, and computer science. The book has two parts. The first part asks "are there voting rules that are truthful?" in the sense that all voters have an incentive to report their true preferences. The seminal Gibbard-Satterthwaite theorem excludes the existence of such voting rules under certain requirements. From this starting point, we survey both extensions of the theorem and various conditions under which truthful voting is made possible (such as restricted preference domains). We also explore the connections with other problems of mechanism design such as locating a facility that serves multiple users. In the second part, we ask "what would be the outcome when voters do vote strategically?" rather than trying to prevent such behavior. We overview various game-theoretic models and equilibrium concepts from the literature, demonstrate how they apply to voting games, and discuss their implications on social welfare. We conclude with a brief survey of empirical and experimental findings that could play a key role in future development of game theoretic voting models.