Recursivity

In some cases, a rule or grammatical structure requires to be applied several times to deal with with recursive expressions such as, for instance, “nice red car”. In this expressions the noun “car” is modified by two adjectives in the same way. DepPattern can deal with this phenomenon in several ways: using a block of rules, applying twice the same rule, or using the operator “Recursivity”. The 3 possible representations are the following:

Block of rules:

AdjunctLeft : [ADJ] ADJ NOUN

NEXT

AdjunctLeft : ADJ [ADJ] NOUN

%

Repetition of the same rule:

AdjunctLeft : ADJ NOUN

%

AdjunctLeft : ADJ NOUN

%

Recursivity operator:

AdjunctLeft : ADJ NOUN

Recursivity: 1

%

“Recursivity” is specified by numeric values: “1” means that the rule must be applied twice. By default, the value is 0, that is a rule is applied only once. This operator permits to specifiy the number of times a rule can be applied. It allows both a more compact representation and an easier control of rule recursivity.