The higher-order model defined in this paper decomposes a dependency structure into factors that include children of the head and the modifier.
a factor in our model is represented by the signature f = h, m, l, c h , c mi , c mo where, as in the first-order model, h, m and l are respectively the head, modifier and label of the main dependency of the factor; c h is the child of that is furthest from m; c mo is the child of m outside [h .