Question: Consider the probabilistic experiment given by the protocol R2. Define two indicator variables X1 and X2, where X1 = 1 if and only if the first prime p is good for (x, y) and X2 = 1 if and only if the second prime q is good for (x, y). Prove that X1 and X2 are independent. Can X1 and X2 be used to define the random variable Y used above?