1b would be represented as follows (details omitted): (1) 1 U pron 0 FRAG 2 heeft verb 0 ROOT 3 volkomen adj 4 mod 4 gelijk noun 0 FRAG In the training phase, the MSTParser tries to maximize the scoring margin between the correct parse and all other valid dependency trees for the sentence.
in the case of fragmented trees, the training example is not strictly speaking correct, in the sense that it does not coincide with the desired parse tree.