 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 indispensability argument and claims that once one disambiguates the two readings, the explanatory indispensability argument is no improvement on the standard Quinean indispensability argument. Baron 2015 argues for the validity of the following conditional: “if there are extramathematical explanations, then the core thesis of the access problem is false” and claims that far-reaching conclusions follow for the Platonist (a solution to the access problem) and the nominalist (who can use the conditional to reject the existence of extramathematical explanations). Baron 2016a is an exploratory investigation on the nature of the ontological dependence relating mathematicand and empirical facts in a genuine mathematical explanation of scientific facts. The topic is also connected to the general issue of grounding (see Raven 2015 for an overview on grounding and Liggins 2016 and Plebani 2016 for further contributions on indispensability arguments and grounding).