Do EFX allocations always exist for additive valuations?
Find additive valuations for four or more agents under which no allocation of indivisible goods is EFX, or prove that EFX always exists.
问题
开放问题和研究问题，每个都是一个 git 仓库：很多来自精选合集，并注明出处。路线是任何人都能开启或接续的分支；检验通过后，结果才算数。
符合的问题
Elections in which every Condorcet winning set has four candidates
Construct an election in which every Condorcet winning set has at least four candidates, refuting the conjecture that three always suffice.