remnant: remnant in ellipsis
The remnant relation is used to provide a satisfactory treatment of
ellipsis (in the case of gapping and stripping, where a predicational
or verbal head gets elided). This is something that was lacking in
earlier versions of SD and provides a basis for being able to
reconstruct dependencies in the enhanced representation of UD. In
particular, the goal was to achieve this without having to postulate
empty nodes in the basic representation.
To develop motivation, consider first a sentence without ellipsis:
The question is then how to treat the sentence “Maria foi para Paris e Miriam para Praga”
One option would be to pretend that there is an empty verb and to have the final elements be dependents of it: Maria foi para Paris e Miriam ∅ para Praga. This analysis has some appeal but also has some problems and at any rate stops the basic dependency graph from being simply a tree of dependencies over the words of a sentence. A second option is to simply promote the final elements and to have them as dependents of the main verb of the sentence (foi-2) or of root-0. But then (in general) one loses the ability to successfully reconstruct the correct predicate-argument structure of the sentence from the basic dependency representation.
Therefore, UD adopts an analysis that notes that in ellipsis a
remnant corresponds to a correlate in a preceding clause. The
remnant relation connects each remnant to its correlate in the basic
dependency representation. This is then a sufficient representation to
reconstruct the predicate-argument structure in the enhanced
representation. So, for this example, we have:
Even in the more complex example below, the remnant
relations enable us to correctly retrieve the subjects and objects in
the clauses with an elided verb.
Note in particular that (unlike for conj), remnant uses a chaining analysis where each subsequent remnant depends on the immediately preceding remnant/correlate. The reason for this is that otherwise in a sentence with 2 or more chained ellipses the dependency structure would no longer track which remnants go together. It would become impossible to determine whether Maria ganhou prata and Sandy ouro, or Maria ganhou ouro e Sandy prata.
It is also possible that the incomplete part precedes the complete one in the sentence [de]:
The remnant relation is used when no predicational material is
present. In contrast, in right-node-raising (RNR) and VP-ellipsis
constructions in which some kind of predicational or verbal material
is still present, the remnant relation is not used. In RNR, the
verbs are coordinated and the object is a dobj of the first verb:
In VP-ellipsis, we keep the auxiliary as the head, as shown below:
Treebank Statistics (UD_Portuguese-Bosque)
This relation is universal.
28 nodes (0%) are attached to their parents as remnant.
28 instances of remnant (100%) are left-to-right (parent precedes child).
Average distance between parent and child is 9.28571428571429.
The following 9 pairs of parts of speech are connected with remnant: NOUN-NOUN (11; 39% instances), ADP-NOUN (4; 14% instances), PROPN-PROPN (4; 14% instances), NOUN-NUM (3; 11% instances), ADP-PROPN (2; 7% instances), ADJ-ADJ (1; 4% instances), NOUN-PROPN (1; 4% instances), PRON-PRON (1; 4% instances), SYM-SYM (1; 4% instances).
remnant in other languages: [bg] [cs] [de] [el] [en] [es] [eu] [fa] [fi] [fr] [ga] [he] [hu] [it] [ja] [ko] [sv] [u]