de Marneffe & Nivre 2019: UD enhanced dependencies for English LD and coordination #
Worked English examples illustrating Universal Dependencies' basic vs
enhanced representations (cf. §4.2 and Figure 9 of
[dMN19]). Enhanced graphs are built by adding the
extra arcs with Graph.enhance; per UD v2, coordinators attach via
cc to the conjunct they introduce.
Examples #
Long-distance dependencies #
exWhatDidJohnSee,exWhoSawMary,exWhoDidJohnSee— wh-question fixtures (object extraction, subject question, object withwho).exTheBookThatJohnRead/_enhanced— object relative clause and its enhanced graph.exJohnThinksThatMarySleeps,exJohnThinksMarySleeps,exJohnWondersIfMarySleeps,exJohnWondersWhatMarySaw— complement clauses with and without overt complementizer, with and without embedded extraction.
Coordination #
exJohnAndMarySleep,exJohnSleepsAndMarySleeps— NP and S coordination (no shared-dependent propagation needed).exJohnSeesAndHearsMary/_enhanced— VP coordination; the enhanced graph addsobjfromhearstoMary.exHappyAndSmartBoy— adjective coordination.exRNR/_enhanced— Right Node Raising; the enhanced graph addsobjto the second-conjunct verb.
Implementation notes #
Fixtures use Word.mk' (featureless) except the wh-words; the worked
theorems are structural (Graph.IsTree, arc labels, decide).
Wh-question fixtures #
"What did John see?" — object wh-question (basic tree).
Words: what(0) did(1) John(2) see(3). The wh-word attaches as obj of
the main verb.
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"Who saw Mary?" — subject wh-question (no gap needed).
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"Who did John see?" — object wh-question with who.
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Relative-clause fixtures #
"the book that John read" — object relative clause (basic tree). In UD
the relative clause attaches via acl from head noun to RC verb; the gap
(book as obj of read) is implicit.
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Enhanced graph for "the book that John read": book is added as obj
of read.
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Complement-clause fixtures #
"John thinks that Mary sleeps" — that-complement (no gap).
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"John thinks Mary sleeps" — bare complement (that-omission, no gap).
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"John wonders if Mary sleeps" — if-complement (no gap).
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"John wonders what Mary saw" — embedded wh-question. Words: John(0) wonders(1) what(2) Mary(3) saw(4).
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Coordination fixtures #
"John and Mary sleep" — NP coordination.
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"John sleeps and Mary sleeps" — S coordination.
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"John sees and hears Mary" — VP coordination (basic tree). Mary
attaches as obj of sees only; hears is conj of sees.
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Enhanced graph for "John sees and hears Mary": Mary is obj of
both sees and hears (shared-dep propagation).
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"the happy and smart boy" — adjective coordination.
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"John likes and Mary hates pizza" — Right Node Raising (basic tree).
pizza attaches to likes only.
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Enhanced graph for RNR: pizza is obj of both verbs.
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Conjuncts share their category — the parallelism constraint on coordination ([dMN19] §4.2), study-locally.
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- DeMarneffeNivre2019.ConjunctsCatMatch g = ∀ (v w : Fin n), g.label v w = some UD.DepRel.conj → (g.words v).cat = (g.words w).cat
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Worked theorems — long-distance dependencies #
Object wh-questions have a [wh] filler at position 0.
The enhanced graph for "the book that John read" has the obj-gap arc; the basic tree lacks it.
book gains an unrepresented argument — the gap made explicit.
The enhanced relclause graph violates tree-hood (book now has two
heads), per [dMN19] §4.4; the basic tree is a tree.
Worked theorems — coordination #
Shared-dependent propagation adds the missing obj arc from hears
to Mary; the basic tree lacks it.
Mary gains an unrepresented argument in the enhanced graph.
The enhanced coordination graph violates tree-hood; the basic tree is a tree.
RNR enhancement propagates obj to the second-conjunct verb, and the
result is no longer a tree.