Before concluding this section, let me mention a few additional contributions. Bangu 2013 proposes a challenge for the nominalist by offering a simple example in terms of games between two players and claims that the nominalist, unlike the realist, is unable to account for the common features of certain rearrangements that can only be explained by reference to a common mathematical structure of the rearrangements. Marcus 2013 distinguishes epistemic and metaphysical readings of the explanatory