6. (15 points) In May's theorem, we assume that the voting rule f is anony- mous; namely, any permutation of voters does not affect the outcome. One can consider a weaker symmetry requirement that any two voters play the same role. Formally, a voting rule = f(>,...,n) is said to be equi- table if for any pair of voters i j there is a permutation o of {1,..., n} such that o(i) = j and for any preference profile f(>,...,n) = f(>o(1),..., o(n)). For |A| = 2 alternatives, construct an example of an equitable strategy- proof voting rule that does not belong to the family of threshold rules. Hint: You will need at least 4 voters.