 In the Ellsberg example, we are given \(p(\RED) = \lfrac{1}{3}\) and \(p(\BLACK \lor \YELLOW) = \lfrac{2}{3},\) and so we can assume \(v(\RED) = \lfrac{1}{3}\) and \(v(\BLACK \lor \YELLOW) = \lfrac{2}{3}.\) A person who is “ambiguity averse” will assign \(v(\BLACK) + v(\YELLOW) \le v(\BLACK \lor \YELLOW)\); let us assume \(v(\BLACK) = v(\YELLOW) = \lfrac{1}{9}.\) Similarly, she will assign \(v(\RED \lor \YELLOW) + v(\BLACK) \le 1\); let us assume \(v(\RED \lor \YELLOW) = \lfrac{4}{9}.\)