Finally, P1 allows selective projective parsing: we can, for instance, forbid the crossing of "Noun-Determiner" dependencies if we add the corresponding label type to P (see Section 4.4 for more details of P ) .
the CoNLL data differs slightly from the original Alpino treebank as the corpus has been part-of-speech tagged using a Memory-Based-tagger (Daelemans et al., 1996).