Parameterized Intractability for Multi-Winner Election under the Chamberlin-Courant Rule and the Monroe Rule

02/24/2022

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by   Jiehua Chen, et al.

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TU Wien

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Answering an open question by Betzler et al. [Betzler et al., JAIR'13], we resolve the parameterized complexity of the multi-winner determination problem under two famous representation voting rules: the Chamberlin-Courant (in short CC) rule [Chamberlin and Courant, APSR'83] and the Monroe rule [Monroe, APSR'95]. We show that under both rules, the problem is W[1]-hard with respect to the sum β of misrepresentations, thereby precluding the existence of any f(β) · |I|^O(1) -time algorithm, where |I| denotes the size of the input instance.