Welfare properties and core for a competitive equilibrium without divisible.

We study welfare and core equivalence for a competitive equilibrium defined on an economy where all commodities are indivisible at the individual level, but perfectly divisible at the aggregate level. In our model is assumed that thereexists a continuum parameter, which can be interpreted as fiat money and does not participate in the preferences of individuals and could be used to facilitate exchange. Given the existence of equilibria with a strictly positive price of fiat money, we establish a core equivalence result, and First and Second Welfare Theorems.