Dependencies on heads and head inversion #2
Description
In the conversion from UD to SUD, aux, case, cop and mark relations are inverted. Some dependencies from the old head are moved to the new head, but it is difficult to establish rules for these moves, because the reasons are often semantic.
One principle that works in many cases is to avoid creating non-projective dependencies. For example, consider the following configuration in UD:
VERB -[aux]-> AUX; VERB -[obl:mod]-> COMPL; COMPL < AUX < VERB
The source of the obl:mod dependency must be transferred from VERB to AUX so that a non-projective dependency is not created.
We can also use lexical information to distinguish between dependencies that move and those that do not. For auxand cop dependenvies, adverbs that are sentence modifiers move. This the case for temporal, locative and judgment adverbs.
Example : il est vraisemblablement décédé (he is probably deceased).
UD : décédé -[advmod]-> vraisemblablement
SUD: est -[mod]-> vraisemblablement