 Young’s axioms identify scoring rules out of the set of all functions defined from ballots that are rankings of candidates. In order to characterize the voting methods from Section 2.2, we need to change the set of ballots. For example, in order to characterize Approval Voting, the set of ballots \(\mathcal{B}\) is the set of non-empty subsets of the set of candidates—i.e., \(\mathcal{B}=\wp(X)-\emptyset\) (selecting the ballot \(X\) consisting of all candidates means that the voter abstains). Two additional axioms are needed to characterize Approval Voting: