3.2.1 Accuracy versus number of estimated links. In a given estimation, there is a trade-off between accuracy and number of estimated links n. At the end of the estimation, frequently reinforced links (likely to be the correct ones) will have weights much higher than those infrequently reinforced links (likely to be the wrong ones). To determine which tentative links we would accept as estimated links, we set a cut-off value w C for the weight. Links with weights above w C will be accepted as estimated links, otherwise they are rejected. If w C is large, only a few estimated links are accepted, and most of these will be correct estimates. On the other hand when w C is small, more estimated links are accepted but a larger fraction of these will be wrong. Our simulation results confirmed this and showed that the accuracy falls off very slowly as a power law in the number of estimated links n, with power-law exponents much smaller than 1 (Figure 3 ).