TY - GEN

T1 - Algorithms for gerrymandering over graphs

AU - Ito, Takehiro

AU - Kamiyama, Naoyuki

AU - Kobayashi, Yusuke

AU - Okamot, Yoshio

PY - 2019/1/1

Y1 - 2019/1/1

N2 - We initiate the systematic algorithmic study for gerrymandering over graphs that was recently introduced by Cohen-Zemach, Lewen-berg and Rosenschein. Namely, we study a strategic procedure for a political districting designer to draw electoral district boundaries so that a particular target candidate can win in an election. We focus on the existence of such a strategy under the plurality voting rule, and give interesting contrasts which classify easy and hard instances with respect to polynomial-time solvability. For example, we prove that the problem for trees is strongly NP-complete (thus unlikely to have a pseudo-polynomial-time algorithm), but has a pseudo-polynomial-time algorithm when the number of candidates is constant. Another example is to prove that the problem for complete graphs is NP-complete when the number of electoral districts is two, while is solvable in polynomial time when it is more than two.

AB - We initiate the systematic algorithmic study for gerrymandering over graphs that was recently introduced by Cohen-Zemach, Lewen-berg and Rosenschein. Namely, we study a strategic procedure for a political districting designer to draw electoral district boundaries so that a particular target candidate can win in an election. We focus on the existence of such a strategy under the plurality voting rule, and give interesting contrasts which classify easy and hard instances with respect to polynomial-time solvability. For example, we prove that the problem for trees is strongly NP-complete (thus unlikely to have a pseudo-polynomial-time algorithm), but has a pseudo-polynomial-time algorithm when the number of candidates is constant. Another example is to prove that the problem for complete graphs is NP-complete when the number of electoral districts is two, while is solvable in polynomial time when it is more than two.

KW - Computational social choice

KW - Gerrymandering

KW - Graph algorithms

UR - http://www.scopus.com/inward/record.url?scp=85076885438&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85076885438&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85076885438

T3 - Proceedings of the International Joint Conference on Autonomous Agents and Multiagent Systems, AAMAS

SP - 1413

EP - 1421

BT - 18th International Conference on Autonomous Agents and Multiagent Systems, AAMAS 2019

PB - International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS)

T2 - 18th International Conference on Autonomous Agents and Multiagent Systems, AAMAS 2019

Y2 - 13 May 2019 through 17 May 2019

ER -