Natural extension with independence constraints

The strongest statement considered here is the independence of a variable and its nondescendants given its parents. The natural extension is then derived from the full joint credal set K(f, b), which has six vertices: 1/4 (1, 1, 1, 1), (0.36, 0.24, 0.24, 0.16), 1/10 (2, 2, 3, 3), 1/10 (2, 3, 2, 3), 1/9 (2, 2, 2, 3), 1/11 (2, 3, 3, 3). Computation of p(d|l) in each of the six joint distribution leads to the lower bound 0.3818 and the upper bound 0.4509.