DVote: Constraining Committee Voting with Database Dependencies

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Abstract

Approval-Based Committee (ABC) voting refers to the task of selecting a committee of a desired size, given voter preferences that state the specific candidates that each voter approves of. A voting rule aggregates the voter preferences into a winning committee. As a special case, an ABC scoring rule determines a score that each voter contributes to the committee based on her approvals. Various ways have been proposed to impose constraints on the elected committee. The demonstration presents DVote— a tool that implements a recent framework for extending score-based ABC voting with constraints on the context surrounding the candidates, given as a relational database. DVote provides a convenient interface to set up a voting instance and build contextual constraints in the form of Tuple-Generating Dependencies (TGDs) and Denial Constraints (DCs). The computation of the winning committee is done by backend components that encapsulate the contextual database and translate the entire task of constrained election into Mixed Integer Programming. In the demonstration, attendees will experience ABC voting with DVote in different domains and contexts.