On a result of Aumann and Shapley about values of non-atomic games

We focus our attention on the argument developed by R.J. Aumann and L.S. Shapley in a proposition used to prove the existence of a value on a certain class of games. Since we have found such an argument to be inexact, we have devised a supplementary construction which should be incorporated in the original proof to make it run in a satisfactory way.