Universal Attributes
(→Set of attributes) |
(→Set of attributes) |
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***@anterior: before some other time other than the time of utterance | ***@anterior: before some other time other than the time of utterance | ||
***@posterior: after some other time other than the time of utterance | ***@posterior: after some other time other than the time of utterance | ||
| + | *[[voice]] | ||
| + | **@active: He built this house in 1895 | ||
| + | **@passive: This house was built in 1895. | ||
| + | **@reflexive: He killed himself. | ||
| + | **@reciprocal: They killed each other. | ||
}} | }} | ||
Revision as of 19:39, 24 June 2010
Attributes are arcs linking a node to itself. In opposition to relations, they correspond to one-place predicates, i.e., functions that take a single argument. In UNL, attributes have been normally used to represent information conveyed by natural language grammatical categories (such as tense, mood, aspect, number, etc). The set of attributes, which is claimed to be universal, is defined in the UNL Specs and is not open to frequent additions.
Syntax
The syntax of attributes is defined as follows:
| <attribute> | ::= | "@"<attribute name> |
| <attribute name> | ::= | <character>... |
| <character> | ::= | {“a”,...,“z”,“_”} |
where:
< > variable
" " terminal symbol
::=... is defined as ...
{ } disjunction ("or")
... to be repeated more than 0 times
Attribute names are always lower case words or expressions. Normally, English words ("past", "will") or mnemonic abbreviations ("def", "pl") are used for attribute labelling. No blank space is allowed inside an attribute name ('@double_quote').
Semantics
Attributes are annotations made to nodes or hypernodes of a UNL hypergraph. They denote the circumstances under which these nodes (or hypernodes) are used.
Attributes may convey three different kinds of information:
- The information on the role of the node in the UNL graph (as in the case for '@entry', that indicates the main (starting) node of a UNL directed graph);
- The information on the original co-text (i.e., the textual neighborhoods) from which the node was extracted (as in the case of '@parenthesis', that indicates that the node was originally represented between parentheses); and
- The information on the (external) context of the utterance (as in the case of '@past', that indicates that the node was used in a time before the speaker's one). In that sense, attributes include phenomena associated to the idea of "deixis".
