5.4.4 Role Constraints

For each role \rho\in\setof{Roles} there is a corresponding binary predicate \Gamma_\rho. The third principle of well-formedness requires that whenever the dependency tree contains an edge w\EDGE\rho w', then the grammatical condition \Gamma_\rho(w,w') must hold in the tree. Therefore the tree must satisfy the proposition below:

\forall w,w'\in\VV,\ \forall\rho\in\setof{Roles},\quad

In practice, the proposition will be enforced by creating a disjunctive propagator for each triple (w,w',\rho):


For illustration, let's consider some examples of \Gamma_\rho(w,w').


The subject of a finite verb must be either a noun or a pronoun, it must agree with the verb, and must have nominative case. We write \SET{nom} for the set of agreement tuples with nominative case:



An adjective may modify a noun and must agree with it:


Denys Duchier
Version 1.2.0 (20010221)