There are many reasons why societies run elections. For example, a given society may need
to select its leader (eg, a president), members of a team may need to find an appropriate …

In a typical social choice scenario, agents rank the available alternatives and have to
collectively decide on the best alternative, or a ranking of the alternatives. If there are just …

A committee selection rule (or, multiwinner voting rule) is a map** that takes a collection of
strict preference rankings and a positive integer k as input, and outputs one or more subsets …

We consider approval-based committee voting, ie the setting where each voter approves a
subset of candidates, and these votes are then used to select a fixed-size set of winners …

We study two influential voting rules proposed in the 1890s by Phragmen and Thiele, which
elect a committee of k candidates which proportionally represents the voters. Voters provide …

The goal of multi-winner elections is to choose a fixed-size committee based on voters'
preferences. An important concern in this setting is representation: large groups of voters …

We consider the following problem: There is a set of items (eg, movies) and a group of
agents (eg, passengers on a plane); each agent has some intrinsic utility for each of the …

Social choice becomes easier on restricted preference domains such as single-peaked,
single-crossing, and Euclidean preferences. Many impossibility theorems disappear, the …

In the late 19th century, Swedish mathematician Edvard Phragmén proposed a load-
balancing approach for selecting committees based on approval ballots. We consider three …

We consider the problem of selecting a fixed-size committee based on approval ballots. It is
desirable to have a committee in which all voters are fairly represented. Aziz et al.(2015a; …