6 papers
A Polynomial-Time Rule Satisfying Full Justified Representation
Fabian Frank, Jannik Peters
In approval-based multiwinner voting, voters submit an approval ballot on which basis a committee of fixed size has to be selected. Compared to single-winner voting this makes…
Fractional Pareto-Optimality in Multiwinner Voting
Patrick Becker, Niclas Boehmer, Fabian Frank +1
Efficiency in multiwinner voting is most naturally captured by Pareto-optimality (PO), yet this notion is computationally and structurally difficult to handle. We therefore study f…
Stability Under Valuation Updates in Coalition Formation
Fabian Frank, Matija NovakoviÄ, René Romen
Coalition formation studies how to partition a set of agents into disjoint coalitions under consideration of their preferences. We study the classical objective of stability in a v…
On Minimal Achievable Quotas in Multiwinner Voting
Patrick Becker, Fabian Frank
Justified representation (JR) and extended justified representation (EJR) are well-established proportionality axioms in approval-based multiwinner voting. Both axioms are always s…
Reconfiguring Proportional Committees
Chris Dong, Fabian Frank, Jannik Peters +1
An important desideratum in approval-based multiwinner voting is proportionality. We study the problem of reconfiguring proportional committees: given two proportional committees,…
The Metric Distortion of Randomized Social Choice Functions: C1 Maximal Lottery Rules and Simulations
Fabian Frank, Patrick Lederer
The metric distortion of a randomized social choice function (RSCF) quantifies its worst-case approximation ratio to the optimal social cost when the voters' costs for alternatives…