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 …

We study voting rules for participatory budgeting, where a group of voters collectively
decides which projects should be funded using a common budget. We allow the projects to …

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 …

Group recommendation has attracted significant research efforts for its importance in
benefiting a group of users. This paper investigates the Group Recommendation problem …

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 …

Participatory budgeting enables the allocation of public funds by collecting and aggregating
individual preferences. It has already had a sizable real-world impact, but making the most …

In the Densest k-Subgraph (D k S) problem, given an undirected graph G and an integer k,
the goal is to find a subgraph of G on k vertices that contains maximum number of edges …

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

We study computational aspects of three prominent voting rules that use approval ballots to
elect multiple winners. These rules are satisfaction approval voting, proportional approval …