The dependency relation of certain adjuncts (expressed by adverbs or prepositional phrases) is not always unambiguous: they do not necessarily modifiy only one element within the sentence but they can have a relation to several elements at the same time. Only one dependency relation can be represented by an edge. With adjuncts expressed by adverbs or prepositional phrases, it is often impossible to determine the appropriate dependency relation unambiguously. Only one (basic) dependency relation is represented, then, and no special attributes are established that would express other semantic relations.
For annotation rules of this type of modification see Section 11, "Ambiguous structures".