Semantics in ENJU is represented by predicate-argument structures. The type is defined in the file "grammar/types.lil"．
Predicate-argument structures are assigned to the CONT feature of signs. A predicate-argument structure is represented by the following feature structure:
| feature name | description |
|---|---|
| HOOK | the core of the semantics of the parsed phrase |
| RELS | list of structures that modify the HOOK |
Take the noun phrase "a pretty girl" as an example，the semantic representation of "girl" is assigned to the HOOK feature whereas the representation of the modification of "girl" by "pretty" as a relation is assigned to the RELS feature．
Values assigned to HOOK and RELS are of the type 'relation'． 'relation' has the following two subtypes．
| type name | description |
|---|---|
| ?unknown_relation | represent an unknown entity (such as the subject of a particle) |
| pred_relation | The relation is introduced by a word that forms part of the parsed phrase. The value assigned to the PRED feature is of the type 'lex_entry' and corresponds to the lexical entry of the word. |
The predicate argument structure of a word is represented by subtypes of the type 'pred_relation'．Depending on the number of arguments taken by the word, a subtype of 'pred_relation' may carry the following features, which are assigned the 'relation's corresponding to the arguments taken by the word.
| feature name | description |
|---|---|
| ARG1 | subjects of verbs, modifees of adjectives and prepositions |
| ARG2 | objects of verbs and prepositions, indirect objects of ditransitive verbs |
| ARG3 | direct objects of ditransitive verbs |
| ARG4 | The third object of a verb |
| ARG5 | The fourth object of a verb |
| MODARG | modifiees not assigned to ARG1, like those appear in noun-noun compounds, temporal nouns and gerunds． |
The following subtypes of the 'pred_relation' type is defined:
| type name | description |
|---|---|
| noun_relation | a head noun |
| noun_arg1_relation | a noun that takes one argument |
| noun_mod_relation | a noun-noun compound or a temporal noun |
| noun_mod_arg1_relation | a temporal noun that takes a sentential complement |
| aux_relation | an auxiliary verb |
| aux_mod_relation | to as a particle? |
| verb_arg1_relation | an intransitive verb |
| verb_arg12_relation | a transitive verb or a verb that takes a sentential complement |
| verb_arg123_relation | a verb that takes two np objects or a verb that takes one np object and one sentential complement |
| verb_arg1234_relation | a verb that takes three np objects or sentential complements |
| verb_mod_arg1_relation | an intransitive verb attached to a modifiee |
| verb_mod_arg12_relation | a transitive verb attached to a modifiee |
| verb_mod_arg123_relation | a verb with three objects and a modifier |
| verb_mod_arg1234_relation | a verb with four objects and a modifier |
| adj_relation | adjectives and adverbs |
| adj_arg1_relation | adjectives and adverbs that are attached to a modifiee |
| adj_arg12_relation | adjectives and adverbs that are attached to a modifiee and take a complement |
| adj_arg123_relation | adjectives and adverbs that are attached to a modifiee and take two complement |
| conj_relation | conjunctions |
| conj_arg1_relation | subordinating conjunctions that take one argument |
| conj_arg12_relation | subordinating conjunctions that take two arguments |
| coordination_relation | coordinating conjunctions |
| det_mod_relation | predeterminers |
| det_arg1_relation | determiners(articles) |
| det_arg12_relation | 's |
| prep_relation | prepositions |
| prep_arg12_relation | prepositions that take an objects or are attached to a modifiee |
| prep_arg123_relation | prepositions that take two objects or modifees |
| prep_arg1234_relation | prepositions that take three objects or modifees |
| pl_relation | particles |
| punct_relation | punctuations |
| left_paren_relation | left parentheses |
| right_paren_relation | right parentheses |
| comp_relation | complementizers |
| comp_for_relation | for as a complementizer |
| relative_relation | relative pronouns |
A predicate argument structure of ENJU necessarily introduces one pred relation for each word. Even words that carry no meaning like copular verbs or relative pronouns are assigned a pred relation. Some applications may need such empty relation. If your application have no use of such empty relations, you can extract only the non-empty relations from a predicate argument structures of ENJU.
The predicate argument structure of "a pretty girl" carrying some of the mentioned features is given below:
| hpsg_cont | |||||||||||||||
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