Discourse Representation Theory (DRT)

Origin. Hans Kamp (1981). Discourse referents. DRS structures. Anaphora and scope. Foundation of computational semantics.

Models. Discourse Representation Structures (DRS). Referents introduced and accessed. Anaphora resolution. Scope via embedding. Computational implementation.

Formalism.

DRS structure: ⟨U, Con⟩. U: universe (discourse referents). Con: conditions (predicates on referents). Box notation.

DRS box notation: ┌─────────┐ │ x, y │ ← referents ├─────────┤ │ man(x) │ ← conditions │ loves(x,y)│ └─────────┘

Construction rules: Indefinite: introduces referent. "A man" → add x, man(x). Pronoun: picks up referent. "He" → use accessible x.

Accessibility: Referent accessible if in same or superordinate DRS. Not if in subordinate. "If a man comes, he sits" → accessible. "It's not the case that a man comes. *He sits" → not accessible.

Negation: ¬DRS: subordinate box. Referents trapped inside. Not accessible from outside. Scope island.

Conditionals: If DRS₁ then DRS₂. DRS₁ referents accessible in DRS₂. Not outside. Donkey sentences handled.

Donkey sentences: "If a farmer owns a donkey, he beats it." ∀x,y[(farmer(x) ∧ donkey(y) ∧ owns(x,y)) → beats(x,y)]. Indefinite with universal force. DRT explains.

Symbols.

Symbol	Unicode	Meaning
DRS	—	Discourse Representation Structure
U	—	universe (referents)
Con	—	conditions
⇒	U+21D2	DRS implication

Metatheory. Discourse structure. Accessibility. Anaphora. Scope.

Applies to. Computational semantics. Anaphora. Discourse processing. NLP.

Limitations. Specific phenomena. Dynamic alternatives. Compositional tensions. Complexity.