---
title: "Multi-Winner Elections: Complexity of Manipulation, Control and Winner-Determination"
authors:
  - "Ariel D. Procaccia"
  - "Jeffrey S. Rosenschein"
  - "Aviv Zohar"
doi: ""
url: "https://ijcai.org/proceedings/2007/238"
pdf: "https://ijcai.org/proceedings/2007/0238.pdf"
venue: "Proceedings of the Twentieth International Joint Conference on Artificial Intelligence"
year: 2007
pages: "1476-1480"
track: ""
keywords:
---

# Multi-Winner Elections: Complexity of Manipulation, Control and Winner-Determination

Ariel D. Procaccia, Jeffrey S. Rosenschein, Aviv Zohar

*Proceedings of the Twentieth International Joint Conference on Artificial Intelligence*, pages 1476-1480.

## Abstract

Although recent years have seen a surge of interest in the computational aspects of social choice, no attention has previously been devoted to elections with multiple winners, e.g., elections of an assembly or committee. In this paper, we fully characterize the worst-case complexity of manipulation and control in the context of four prominent multi-winner voting systems. Additionally, we show that several tailor-made multi-winner voting schemes are impractical, as it is NP-hard to select the winners in these schemes.