New Candidates Welcome! Possible Winners with respect to the Addition of New Candidates

TL;DR

This paper investigates the problem of identifying potential winners among initial candidates when new candidates are added in voting systems, focusing on scoring rules and comparing with related control problems.

Contribution

It provides a computational analysis of possible winners with added candidates under scoring rules and compares this problem to existing control and cloning problems.

Findings

Analysis of computational complexity for possible winners with new candidates

Formal comparison with control via adding candidates and cloning problems

Insights into voting rule robustness with candidate additions

Abstract

In voting contexts, some new candidates may show up in the course of the process. In this case, we may want to determine which of the initial candidates are possible winners, given that a fixed number $k$ of new candidates will be added. We give a computational study of this problem, focusing on scoring rules, and we provide a formal comparison with related problems such as control via adding candidates or cloning.