The increment w ∆ is the difference between the weights for the best active item reaching position i + 1 and the best active item reaching position i.
from now on when we compare the weights for two items x j and x k , with end positions j and k respectively (j < k), then we always add to the score w x j of the first item a fraction of the sum of the increments for the positions between j and k. instead of using w x j when comparing with w x k , we use We call the constant h ∈ [0, 1] the "heuristics factor".