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Combining Montague semantics and discourse representation

Muskens, R. (1996). Linguistics and Philosophy, 19(2), 143–186

Muskens treats the boxes of discourse representation theory as relations between states, so that word meanings combine by function application and sequencing as in Montague semantics. This file gives his lexicon over the register structures of Semantics/Dynamic/RegisterStructure.lean and computes the meanings of his example sentences.

Implementation notes

Static predicates are sets, so an atomic condition is a preimage. A dynamic predicate takes the value function of a referent rather than its register, and names, pronouns and traces mean Function.eval δ for their referent δ. Conjunction at every category is the product of the update monoid lifted pointwise, so conjoined verb phrases and noun phrases multiply with *.

TODO

  • Muskens's box language with sequencing, its translation into first-order logic, and his propositions about that translation. The one relating properness to closed formulas needs the free variables of DRS.toFormula, which mathlib does not yet compute for relabel and iExs.

References

The lexicon

L62–65
L85–88

The paper's derivations

The text reduces by merging to the box (20).

theorem text_eq_boxL112–124
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} [DecidableEq R] (h : u₁ ≠ u₂) (man woman : Set E) (adores abhors : SetRel E E) :
text u₁ u₂ man woman adores abhors = DynamicSemantics.Update.box {u₁, u₂} (DynamicSemantics.RegisterStructure.val u₁ ⁻¹' man ∩ (DynamicSemantics.RegisterStructure.val u₂ ⁻¹' woman ∩ {i : S | (DynamicSemantics.RegisterStructure.val u₁ i, DynamicSemantics.RegisterStructure.val u₂ i) ∈ adores}) ∩ {i : S | (DynamicSemantics.RegisterStructure.val u₂ i, DynamicSemantics.RegisterStructure.val u₁ i) ∈ abhors})

Built from

The truth conditions (24) of the text.

theorem dom_textL126–131
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (man woman : Set E) (adores abhors : SetRel E E) :
SetRel.dom (text u₁ u₂ man woman adores abhors) = {_i : S | ∃ (x₁ : E) (x₂ : E), x₁ ∈ man ∧ x₂ ∈ woman ∧ (x₁, x₂) ∈ adores ∧ (x₂, x₁) ∈ abhors}

Built from

The ∃∀ reading of (33) comes from (35), with the indefinite's referent available to a later pronoun ((41)).

theorem dom_everyWideL149–156
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (girl boy : Set E) (adores : SetRel E E) :
SetRel.dom (everyWide u₁ u₂ girl boy adores) = {_i : S | ∃ x₂ ∈ boy, ∀ x₁ ∈ girl, (x₁, x₂) ∈ adores}

Built from

The conditional has the truth conditions (8), in which the indefinites of the antecedent bind the pronouns of the consequent with universal force.

theorem dom_conditionalL163–170
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (man woman : Set E) (bores ignores : SetRel E E) :
SetRel.dom (conditional u₁ u₂ man woman bores ignores) = {_i : S | ∀ (x₁ x₂ : E), x₁ ∈ man ∧ x₂ ∈ woman ∧ (x₁, x₂) ∈ bores → (x₂, x₁) ∈ ignores}

Built from

The truth conditions of (52).

theorem dom_vpCoordL178–183
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (cat fish : Set E) (catches eats : SetRel E E) :
SetRel.dom (vpCoord u₁ u₂ cat fish catches eats) = {_i : S | ∃ (x₂ : E) (x₁ : E), x₂ ∈ cat ∧ x₁ ∈ fish ∧ (x₂, x₁) ∈ catches ∧ (x₂, x₁) ∈ eats}

Built from

The truth conditions (60) of (58).

theorem dom_npCoordL190–196
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (john : E) (girl boy : Set E) (admires loves : SetRel E E) :
SetRel.dom (npCoord u₁ u₂ john girl boy admires loves) = {_i : S | ∃ (x₁ : E) (x₂ : E), x₁ ∈ girl ∧ (john, x₁) ∈ admires ∧ x₂ ∈ boy ∧ (x₂, x₁) ∈ loves ∧ (john, x₂) ∈ admires}

Built from

The truth conditions (65) of (61) are an open formula, which reads the pronoun's referent off the input state.

theorem dom_npCoord_noL205–212
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] {u₁ u₂ : R} (h : u₁ ≠ u₂) (john : E) (girl boy : Set E) (admires loves : SetRel E E) :
SetRel.dom (npCoordNo u₁ u₂ john girl boy admires loves) = {i : S | ∃ (x₂ : E), (¬∃ x₁ ∈ girl, (john, x₁) ∈ admires) ∧ x₂ ∈ boy ∧ (x₂, DynamicSemantics.RegisterStructure.val u₁ i) ∈ loves ∧ (john, x₂) ∈ admires}

Built from

L214–216
L219–224

The boxes of (67) do not merge when Bill and Sue own only different donkeys.

theorem reassignment_ne_mergeL233–248
{R : Type u_1} {S : Type u_2} {E : Type u_3} [DynamicSemantics.RegisterStructure R S E] [Nonempty S] {u₃ : R} {bill sue : E} {donkey : Set E} {owns : SetRel E E} (hb : ∃ x ∈ donkey, (bill, x) ∈ owns) (hs : ∃ x ∈ donkey, (sue, x) ∈ owns) (h : ¬∃ x ∈ donkey, (bill, x) ∈ owns ∧ (sue, x) ∈ owns) :
reassignment u₃ bill sue donkey owns ≠ DynamicSemantics.Update.box {u₃} (DynamicSemantics.RegisterStructure.val u₃ ⁻¹' donkey ∩ {i : S | (bill, DynamicSemantics.RegisterStructure.val u₃ i) ∈ owns} ∩ (DynamicSemantics.RegisterStructure.val u₃ ⁻¹' donkey ∩ {i : S | (sue, DynamicSemantics.RegisterStructure.val u₃ i) ∈ owns}))

Built from

Properness is representational (§III.5)

A proper box and a box that is not proper may have the same semantic value: (45), the translation of "No¹ girl walks", and (47), that of "*No¹ girl walks. If she₁ talks she₁ talks", denote the same relation in every model, but only (45) is proper. Acceptability of an indexing is therefore a property of its representation, which is why Muskens simplifies translations by lambda conversion and merging only.

fn. 4: the total-assignment semantics and re-declared referents

Muskens 1996's fn. 4 scopes the agreement of his semantics with standard DRT to total assignments and notes a second difference: on [ | [x | man x] ⇒ [x | mortal x]], where x is declared twice, standard DRT ignores the second declaration and says that every man is mortal, while here the second x takes a new value and the box says that there is a mortal if there is a man. The partial semantics DRS.Verifies (Verification/Partial.lean) renders standard DRT: the re-declaration is inert, and in a model with a non-mortal man the two truth values differ (fn4_diverges). The witness is proper (fn4_isProper), so what fails is reuse-freeness (fn4_not_reuseFreeAt), the hypothesis of the reconciliation DRS.trueRel_iff_exists_verifies.

L331–336