D-rule

D-rules or disambiguation rules are used to prevent wrong lexical choices, to provoke best matches and to check the consistency of graphs, trees and lists. Differently from t-rules, they do not provoke transformations, but induce or block them, by assigning priorities to natural language phenomena. The set of d-rules form the Disambiguation grammar, or D-Grammar.

Syntax

D-rules follow the general syntax (UNL Grammar Specs):

STATEMENT=P;

Where
STATEMENT is the left side (condition) of a L-rule or a S-rule; and
P, which can range from 0 (impossible) to 255 (necessary), is the probability of occurrence of the STATEMENT

Types of Disambiguation Rules

There are three types of disambiguation rules:

• Network disambiguation rules
• Tree disambiguation rules
• List disambiguation rules

Network Disambiguation Rules

Network disambiguation rules apply over the network structure of UNL graphs to constrain the application of Tree-to-Network (TN) and Network-to-Network (NN) Transformation Rules. They have the following format:

SEM(A;B)=P;

Where SEM is a semantic relation, A and B are nodes, and P is an integer (from 0 to 255).

Examples

agt(VER;ADJ)=0;

An adjective (ADJ) may not be an agent (agt) of a verb (VER).

agt(VER;NOU)=255;

Agents (agt) of verbs (VER) are always nouns (NOU).

Use

INPUT	TRANSFORMATION RULES	DISAMBIGUATION RULES	OUTPUT
SYN(A,B,C;D,E,F)	SYN(A;D)=agt(;); (higher priority) SYN(A;E)=aoj(;); (lower priority)	agt(A;F)=0;	aoj(A,B,C;D,E,F)

Tree Disambiguation Rules

Tree disambiguation rules apply over the intermediate tree structure to constrain the application of List-to-Tree (LT), Network-to-Tree (NT) and Tree-to-Tree (TT) Transformation Rules. They have the following format:

SYN(A;B)=P;

Where SYN is a syntactic relation, A and B are nodes, and P is an integer (from 0 to 255).

Examples

VS(VER;ADJ)=0;

An adjective (ADJ) may not be an specifier (VS) of a verb (VER).

NS(NOU;DET)=255;

Determiners (DET) are always specifiers (NS) of nouns (NOU).

Use

INPUT	TRANSFORMATION RULES	DISAMBIGUATION RULES	OUTPUT
(A,B,C)(D,E,F)	(A)(D)=X(A;D); (higher priority) (A)(E)=X(E;A); (lower priority)	X(F;A)=255;	X(D,E,F;A,B,C)
agt(A,B,C;D,E,F)	agt(A;D)=X(A;D); (higher priority) agt(A;E)=Y(A;E); (lower priority)	X(B;F)=0;	Y(A,B,C;D,E,F)

List Disambiguation Rules

List disambiguation rules apply over the natural language list structure to constrain the application of both Tree-to-List (TL) and List-to-List (LL) Transformation Rules. They are also used for word selection. They have the following format:

(A)(B)=P;

Where A and B are nodes, and P is an integer (from 0 to 255).

Examples

(ART)(BLK)(VER)=0;

An article (ART) may not precede a verb (VER).

(ART)(BLK)(NOU)=255;

Articles (ART) always precede nouns (NOU).

Use

Rule Disambiguation

INPUT	TRANSFORMATION RULES	DISAMBIGUATION RULES	OUTPUT
X(A,B,C;D,E,F)	X(A;D)=(A)(D); (higher priority) X(A;F)=(F)(A); (lower priority)	(B)(E)=0;	(D,E,F)(A,B,C)

Word Disambiguation

INPUT	DICTIONARY	DISAMBIGUATION RULES	OUTPUT
the book	[book] "22222" (POS=VER); (higher priority) [book] "11111" (POS=NOU); (lower priority)	(ART)(BLK)(VER)=0;	[book] "1111" (POS=NOU);

Formal Syntax of Disambiguation Rules

Disambiguation rules must comply with the following syntax

<DISAMBIGUATION RULE> ::= <NN RULE> | <TT RULE> | <LL RULE> 
<NN RULE>             ::= (<SEM>)+ "=" [0-255]";"
<TT RULE>             ::= (<SYN>)+ "=" [0-255]";"
<LL RULE>             ::= "(" <NODE> ")" ( "(" <NODE> ")" )+ "=" [0-255]";"
<SEM>                 ::= <TEXT> "(" <NODE> ";" <NODE> ")"
<SYN>                 ::= <TEXT> "(" <NODE> ";" <NODE> ")"
<NODE>                ::= ( (<DESCRIPTION>)( "," <DESCRIPTION> )* )?
<DESCRIPTION>         ::= <STRING> | <ENTRY> | <FEATURE> | <RELATION>
<STRING>              ::= """<text>"""
<ENTRY>               ::= "["<entry>"]"
<FEATURE>             ::= <VALUE> | <ATTRIBUTE> | <ATTRIBUTE>"="<VALUE>
<RELATION>            ::= <SEM>|<SYN>
<VALUE>               ::= <TEXT>
<ATTRIBUTE>           ::= <TEXT>
<TEXT>                ::= any sequence of characters except whitespace | <REGULAR EXPRESSION>
<REGULAR EXPRESSION>  ::= "/"<PERL COMPATIBLE REGULAR EXPRESSIONS>"/"

Examples

• List structures
  • (ART)(BLK)(VER)=0; (an article (ART) may not precede a verb (VER))
  • (ART)(BLK)(NOU)=255; (articles (ART) always precede nouns (NOU))
• Syntactic structures
  • agt(VER;ADJ)=0; (an adjective (ADJ) may not be an agent (agt) of a verb (VER))
  • agt(VER;NOU)=255; (agents (agt) of verbs (VER) are always nouns (NOU))
  • VS(VER;ADJ)=0; (an adjective (ADJ) may not be an specifier (VS) of a verb (VER))
  • NS(NOU;DET)=255; (determiners (DET) are always specifiers (NS) of nouns (NOU))