Hyper-relation
From UNL Wiki
(Difference between revisions)
(→Properties of hyper-relations) |
(→Notation) |
||
| Line 9: | Line 9: | ||
== Notation == | == Notation == | ||
Hyper-relations and relations are represented in the same way, i.e., | Hyper-relations and relations are represented in the same way, i.e., | ||
| − | rel(arg1;arg2;...;argn) | + | rel:scope(arg1;arg2;...;argn) |
where: | where: | ||
| − | *rel is the name of the relation | + | *rel is the name of the hyper-relation |
| − | *arg1, arg2, ... are the arguments of the relation | + | *scope is the [[scope]] of the hyper-relation |
| − | The only difference between relations and hyper-relations is that the latter has at least one relation as one of its arguments. | + | *arg1, arg2, ... are the arguments of the hyper-relation |
| + | The only difference between relations and hyper-relations is that the latter has at least one relation as one of its arguments, e.g.: | ||
| + | *rel(rel1(arg1;arg2);arg3;...;argn) | ||
== Examples == | == Examples == | ||
Revision as of 19:22, 19 August 2013
Hyper-relation is a relation between relations, or between relations and nodes.
Contents |
Basic Symbols
| Symbol | Definition | Example |
|---|---|---|
| ( ) | node | (%a) |
| " " | string | "went" |
| [ ] | natural language entry (headword) | [go] |
| [[ ]] | UW | [[to go(icl>to move)]] |
| // | regular expression | /a{2,3}/ = aa,aaa |
| rel(x;y) | relation | agt(kill;Peter) |
| ^ | not | ^a = not a |
| { | } | or | {a|b} = a or b |
| % | index for nodes, attributes and values | %x |
| : | scope ID | :01 |
| # | index for sub-NLWs | #01 |
| = | attribute-value assignment | POS=NOU |
| ! | rule trigger | !PLR |
| & | merge operator | %x&%y |
| ? | dictionary lookup operator | ?[a] |
Basic Concepts
- Node
- A node is the most elementary unit in the graph. It is the result of the tokenization process, and corresponds to the notion of "lexical item". At the surface level, a natural language sentence is considered a list of nodes, and a UNL graph a set of relations between nodes.
- Relation
- In order to form a natural language sentence or a UNL graph, nodes are inter-related by relations. In the UNL framework, there are three different types of relations: the linear (list) relation, syntactic relations and semantic relations.
- Hyper-Node
- A hyper-node is a sub-graph, i.e., a scope: a node containing relations between nodes.
- Hyper-Relation
- A hyper-relation is a relation between relations.
Notation
Hyper-relations and relations are represented in the same way, i.e.,
rel:scope(arg1;arg2;...;argn)
where:
- rel is the name of the hyper-relation
- scope is the scope of the hyper-relation
- arg1, arg2, ... are the arguments of the hyper-relation
The only difference between relations and hyper-relations is that the latter has at least one relation as one of its arguments, e.g.:
- rel(rel1(arg1;arg2);arg3;...;argn)
Examples
Examples of hyper-relations
- XP(XB(%a;%b);%c) - a syntactic relation XP between the syntactic relation XB(%a;%b) and the node %c
- and(agt([a];[b]);agt([a];[c])) - a semantic relation "and" between the semantic relations agt([a];[b]) AND agt([a];[c])
Properties of hyper-relations
- A hyper-relation may have one single relation as each argument
- XP(XB(%a;%b);%c) - the source argument of the hyper-relation XP is a relation
- XP(%a;XB(%b;%c)) - the target argument of the hyper-relation XP is a relation
- XP(VC(%a;%b);VA(%a;%c)) - the source and the target argument of the hyper-relation XP are relations
XP(VC(%a;%b)VA(%a;%c);VS(%a;%d))- a hyper-relation may not have more than one relation as one single argument (in this case, the hyper-relation XP contained two relations as the source argument)
- Differently from nodes, relations do not have elements (strings, headwords, features and elements)
XP(XB(%a;%b),"ab",[ab],[[ab]],A,B;%c)(the relation XB(%a;%b) may not have strings, UWs, headwords or any features)
