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:
Marie went to Paris and Miriam went to Prague
nsubj(went-2, Marie-1)
root(root-0, went-2)
nmod(went-2, Paris-4)
case(Paris-4, to-3)
cc(went-2, and-5)
nsubj(went-7, Miriam-6)
conj(went-2, went-7)
case(Prague-9, to-8)
nmod(went-7, Prague-9)
The question is then how to treat: Marie went to Paris and Miriam to Prague
Marie went to Paris and Miriam to Prague
nsubj(went-2, Marie-1)
root(root-0, went-2)
nmod(went-2, Paris-4)
case(Paris-4, to-3)
cc(went-2, and-5)
case(Prague-8, to-7)
One option would be to pretend that there is an empty verb and to have the final elements be dependents of it: Marie went to Paris and Miriam ∅ to Prague. 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 (went-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:
Marie went to Paris and Miriam to Prague
nsubj(went-2, Marie-1)
root(root-0, went-2)
nmod(went-2, Paris-4)
case(Paris-4, to-3)
cc(went-2, and-5)
remnant(Marie-1, Miriam-6)
case(Prague-8, to-7)
remnant(Paris-4, Prague-8)
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.
John won bronze , Mary silver , and Sandy gold
nsubj(won-2, John-1)
dobj(won-2, bronze-3)
remnant(John-1, Mary-5)
remnant(Mary-5, Sandy-9)
remnant(bronze-3, silver-6)
remnant(silver-6, gold-10)
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 Mary won silver and Sandy gold, or Mary won gold and Sandy silver.
It is also possible that the incomplete part precedes the complete one in the sentence [de]:
während 78 Prozent sich für Bush und vier Prozent für Clinton aussprachen \n while 78 percent REFL for Bush and four percent for Clinton spoke-out
nsubj(aussprachen, Prozent-9)
nsubj(spoke-out, percent-22)
nmod(aussprachen, Clinton-11)
nmod(spoke-out, Clinton-24)
remnant(Prozent-9, Prozent-3)
remnant(percent-22, percent-16)
remnant(Clinton-11, Bush-6)
remnant(Clinton-24, Bush-19)
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:
John bought and ate an apple
nsubj(bought-2, John-1)
cc(bought-2, and-3)
conj(bought-2, ate-4)
det(apple-6, an-5)
dobj(bought-2, apple-6)
In VP-ellipsis, we keep the auxiliary as the head, as shown below:
John will win gold and Mary will too
nsubj(win-3, John-1)
aux(win-3, will-2)
dobj(win-3, gold-4)
cc(win-3, and-5)
conj(win-3, will-7)
nsubj(will-7, Mary-6)
advmod(will-7, too-8)
remnant in other languages: [bg] [cs] [de] [el] [en] [es] [eu] [fa] [fi] [fr] [ga] [he] [hu] [it] [ja] [ko] [sv] [u]