1,287 research outputs found
Sub-committee Approval Voting and Generalised Justified Representation Axioms
Social choice is replete with various settings including single-winner
voting, multi-winner voting, probabilistic voting, multiple referenda, and
public decision making. We study a general model of social choice called
Sub-Committee Voting (SCV) that simultaneously generalizes these settings. We
then focus on sub-committee voting with approvals and propose extensions of the
justified representation axioms that have been considered for proportional
representation in approval-based committee voting. We study the properties and
relations of these axioms. For each of the axioms, we analyse whether a
representative committee exists and also examine the complexity of computing
and verifying such a committee
A Unified Framework of Multi-Stage Multi-Winner Voting: An Axiomatic Exploration
Multi-winner voting plays a crucial role in selecting representative
committees based on voter preferences. Previous research has predominantly
focused on single-stage voting rules, which are susceptible to manipulation
during preference collection. In order to mitigate manipulation and increase
the cost associated with it, we propose the introduction of multiple stages in
the voting procedure, leading to the development of a unified framework of
multi-stage multi-winner voting rules. To shed light on this framework of
voting methods, we conduct an axiomatic study, establishing provable conditions
for achieving desired axioms within our model. Our theoretical findings can
serve as a guide for the selection of appropriate multi-stage multi-winner
voting rules
Multi-Winner Voting with Approval Preferences
Approval-based committee (ABC) rules are voting rules that output a
fixed-size subset of candidates, a so-called committee. ABC rules select
committees based on dichotomous preferences, i.e., a voter either approves or
disapproves a candidate. This simple type of preferences makes ABC rules widely
suitable for practical use. In this book, we summarize the current
understanding of ABC rules from the viewpoint of computational social choice.
The main focus is on axiomatic analysis, algorithmic results, and relevant
applications.Comment: This is a draft of the upcoming book "Multi-Winner Voting with
Approval Preferences
Proportionality in Approval-Based Participatory Budgeting
The ability to measure the satisfaction of (groups of) voters is a crucial
prerequisite for formulating proportionality axioms in approval-based
participatory budgeting elections. Two common - but very different - ways to
measure the satisfaction of a voter consider (i) the number of approved
projects and (ii) the total cost of approved projects, respectively. In
general, it is difficult to decide which measure of satisfaction best reflects
the voters' true utilities. In this paper, we study proportionality axioms with
respect to large classes of approval-based satisfaction functions. We establish
logical implications among our axioms and related notions from the literature,
and we ask whether outcomes can be achieved that are proportional with respect
to more than one satisfaction function. We show that this is impossible for the
two commonly used satisfaction functions when considering proportionality
notions based on extended justified representation, but achievable for a notion
based on proportional justified representation. For the latter result, we
introduce a strengthening of priceability and show that it is satisfied by
several polynomial-time computable rules, including the Method of Equal Shares
and Phragm\`en's sequential rule
Multi-Winner Voting with Approval Preferences
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
Line-Up Elections: Parallel Voting with Shared Candidate Pool
We introduce the model of line-up elections which captures parallel or
sequential single-winner elections with a shared candidate pool. The goal of a
line-up election is to find a high-quality assignment of a set of candidates to
a set of positions such that each position is filled by exactly one candidate
and each candidate fills at most one position. A score for each
candidate-position pair is given as part of the input, which expresses the
qualification of the candidate to fill the position. We propose several voting
rules for line-up elections and analyze them from an axiomatic and an empirical
perspective using real-world data from the popular video game FIFA.Comment: Accepted to SAGT 202
Popular Sovereign Generated Versus Government Institution Generated Constitutional Norms: When Does a Constitutional Amendment Not Amend the Constitution?
An elementary principle of constitutional law is that a constitutional amendment nullifies, or at least alters, preexisting and conflicting constitutional provisions. Yet should all constitutional amendments have this effect? Can we imagine a scenario in which ratification of a new constitutional amendment would leave preexisting conflicting constitutional provisions fully intact, unaltered, and undisturbed? This Article argues that the best understanding of fundamental adjudicatory principles compels us to recognize just such a possibility
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