 While the arrows mark relations of probabilistic dependence, the equations characterize the nature of the dependence, e.g., “\(H\dequal F\lor G\)” means that the value of H is determined by the value of \(F\lor G\) (but not vice versa).[11]  This significantly reduces the number of values that must be  stored.[12]  But it also stores information that is useful to agents. It facilitates counterfactual reasoning—e.g., if C had been true then G would have been true—reasoning about actions—e.g., if we do A then C will be true—and explanatory reasoning—e.g., H is true in part because C is true (Pearl 2002).