Documentation

Studies.GuerriniWehbe2025

Guerrini and Wehbe (2025): Homogeneity as presuppositional exhaustification #

Guerrini and Wehbe derive homogeneity by presuppositional exhaustification. A plural definite contributes Bar-Lev's existential pluralization, and the operator pex of Del Pinal, Bassi and Sauerland asserts it while presupposing that its subdomain alternatives are all true or all false. Accommodating the presupposition yields the universal reading as long as no alternative for a single atom is pruned (pexPlural_eq_one_iff), and pruning those yields non-maximal readings, at least two of three students for the pairs of (21) (pexPlural_pairs_eq_one_iff). Under negation the presupposition projects and the negated existential already entails it, so pruning has no effect (pexPlural_eq_neg_one_iff). Non-maximality under negation needs local accommodation below negation and a second pex over the negated universal, which is the positive case for the negated predicate (localAccommodation_nonMaximal).

Homogeneity is thus a presupposition, which a constraint on accommodation detects: a sentence is felicitous only if its assertion is informative once its presupposition is accommodated (Informative, the paper's (8)). She read the books is infelicitous where Mary is known to have read some of them, the candidates lost where at most one candidate can win, and their negations where the universal is known to fail, while the quantified counterparts are fine (judgments_10, judgments_13).

Implementation notes #

A plurality is the domain of Bar-Lev's existential pluralization, the disjunction of its atoms, and the alternatives are his subdomain alternatives, the sub-disjunctions, all of which are innocently includable (Exhaustification.II_eq_self_of_subset_supClosure). The common ground is a set of worlds and accommodation intersects it with the presupposition. The higher pex of (24) and (27) does not change the truth conditions of a negated plural and is not modelled.

TODO #

References #

Presuppositional exhaustification of plural predication (§4) #

@[reducible, inline]
noncomputable abbrev GuerriniWehbe2025.pexPlural {Atom : Type u_1} {W : Type u_2} [DecidableEq Atom] (D x : Finset Atom) (P : Atom → W → Prop) (R : Set (Set W)) :
W → SignType

A plural predication under pex, (19), asserts Bar-Lev's existential pluralization and presupposes that its relevant subdomain alternatives are homogeneous.

Equations
Instances For
    theorem GuerriniWehbe2025.pexPlural_ne_zero_iff {Atom : Type u_1} {W : Type u_2} [DecidableEq Atom] {D x : Finset Atom} {P : Atom → W → Prop} {R : Set (Set W)} {w : W} (h : BarLev2021.Separating D x P) (hne : (x ∩ D).Nonempty) :
    pexPlural D x P R w ≠ 0 ↔ Homogeneity.Homogeneous (supClosure (BarLev2021.atom P '' ↑(x ∩ D)) \ {⋃ b ∈ x ∩ D, BarLev2021.atom P b} ∩ R) w

    The presupposition (19b) is that the relevant subdomain alternatives are all true or all false.

    theorem GuerriniWehbe2025.pexPlural_eq_one_iff {Atom : Type u_1} {W : Type u_2} [DecidableEq Atom] {D x : Finset Atom} {P : Atom → W → Prop} {R : Set (Set W)} {w : W} (h : BarLev2021.Separating D x P) (hcard : 1 < (x ∩ D).card) (hR : ∀ a ∈ x ∩ D, BarLev2021.atom P a ∈ R) :
    pexPlural D x P R w = 1 ↔ ∀ a ∈ x, a ∈ D → P a w

    In (20), after accommodation, a plural predication is universal as long as no alternative for a single atom is pruned.

    theorem GuerriniWehbe2025.pexPlural_eq_neg_one_iff {Atom : Type u_1} {W : Type u_2} [DecidableEq Atom] {D x : Finset Atom} {P : Atom → W → Prop} {R : Set (Set W)} {w : W} :
    pexPlural D x P R w = -1 ↔ ∀ a ∈ x, a ∈ D → ¬P a w

    In (25) and (28), a negated plural predication is true exactly where no atom satisfies the predicate, however the alternatives are pruned.

    Post-Accommodation Informativity (§3) #

    def GuerriniWehbe2025.Informative {W : Type u_1} (c : Set W) (S : W → SignType) :

    A sentence is informative in the common ground c after accommodation, Post-Accommodation Informativity (8), when it is false at some world of c, its presupposition holding there.

    Equations
    Instances For
      theorem GuerriniWehbe2025.Informative.mono {W : Type u_1} {c c' : Set W} {S : W → SignType} (h : Informative c S) (hcc' : c ⊆ c') :
      theorem GuerriniWehbe2025.not_informative_pexPlural {W : Type u_1} {Atom : Type u_2} [DecidableEq Atom] {D x : Finset Atom} {P : Atom → W → Prop} {R : Set (Set W)} :
      ¬Informative (⋃ b ∈ x ∩ D, BarLev2021.atom P b) (pexPlural D x P R)

      Where the existential is common ground, a plural predication asserts nothing new, (10a) and (13d).

      theorem GuerriniWehbe2025.not_informative_neg {W : Type u_1} {Atom : Type u_2} [DecidableEq Atom] {D x : Finset Atom} {P : Atom → W → Prop} {R : Set (Set W)} (h : BarLev2021.Separating D x P) (hcard : 1 < (x ∩ D).card) (hR : ∀ a ∈ x ∩ D, BarLev2021.atom P a ∈ R) :
      ¬Informative {w : W | ¬∀ a ∈ x, a ∈ D → P a w} (-pexPlural D x P R)

      Where the universal is known to fail, the negated plural predication asserts nothing new once homogeneity is accommodated, (10b), (12b), (13c) and (23).

      Three students (§4, §5) #

      Worlds record who smiled, and holds a w says that a smiled at w.

      theorem GuerriniWehbe2025.pexPlural_pairs_eq_one_iff (w : Finset (Fin 3)) :
      pexPlural Finset.univ Finset.univ BarLev2021.holds (Exhaustification.subDisjsOfCard Finset.univ (BarLev2021.atom BarLev2021.holds) 2) w = 1 ↔ 2 ≤ w.card

      In (21), pruning to the alternatives over pairs of the three students makes the students smiled true after accommodation where at least two of them smiled.

      @[reducible, inline]
      abbrev GuerriniWehbe2025.notSmiled (a : Fin 3) (w : Finset (Fin 3)) :

      Student a did not smile at w.

      Equations
      Instances For
        theorem GuerriniWehbe2025.localAccommodation_eq_one_iff (w : Finset (Fin 3)) :
        pexPlural Finset.univ Finset.univ notSmiled (supClosure (Set.range (BarLev2021.atom notSmiled))) w = 1 ↔ w = ∅

        In (31), with homogeneity accommodated below negation and no pruning, the students didn't smile is true where none of them smiled.

        theorem GuerriniWehbe2025.localAccommodation_nonMaximal :
        pexPlural Finset.univ Finset.univ notSmiled (supClosure (Set.range (BarLev2021.atom notSmiled)) \ {BarLev2021.atom notSmiled 2}) {2} = 1

        In (32)–(34), pruning the alternative for the third student makes the students didn't smile true when only that student smiled, a non-maximal reading under negation.

        The judgments of §3 #

        Each sentence is judged against the common ground its context sets up. Worlds record which books Mary read, which teammates John is married to, which candidates won, or which students smiled.

        theorem GuerriniWehbe2025.judgments_9 :
        (Examples.ex_9a.judgment = Judgment.acceptable ↔ Informative {w : ℕ × Bool | w.2 = true} ({w : ℕ × Bool | w.1 = 10}.indicator fun (w : ℕ × Bool) => SignType.ofProp (w.2 = true))) ∧ (Examples.ex_9b.judgment = Judgment.acceptable ↔ Informative {w : ℕ × Bool | w.2 = true} fun (w : ℕ × Bool) => SignType.ofProp (w.1 = 10 ∧ w.2 = true))

        In (9), with John's kids known to be adopted, all 10 of John's kids are adopted asserts nothing once its presupposition that he has 10 kids is accommodated, while John has 10 adopted kids is informative. A world records how many kids John has and whether they are all adopted.

        theorem GuerriniWehbe2025.judgments_10 :
        (Examples.ex_10a.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w.Nonempty} (pexPlural Finset.univ Finset.univ BarLev2021.holds (supClosure (Set.range (BarLev2021.atom BarLev2021.holds))))) ∧ (Examples.ex_10b.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w ≠ Finset.univ} (-pexPlural Finset.univ Finset.univ BarLev2021.holds (supClosure (Set.range (BarLev2021.atom BarLev2021.holds)))))

        In (10), with Mary known to have read some of the books, she read the books asserts nothing new, and with her known not to have read all of them, neither does she didn't read the books.

        theorem GuerriniWehbe2025.judgments_12 :
        (Examples.ex_12a.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w ≠ Finset.univ} fun (w : Finset (Fin 2)) => SignType.ofProp (w = ∅)) ∧ (Examples.ex_12b.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w ≠ Finset.univ} (-pexPlural Finset.univ Finset.univ BarLev2021.holds (supClosure (Set.range (BarLev2021.atom BarLev2021.holds)))))

        In (12), since John is not married to all of his teammates, John isn't married to any of his teammates is informative, but John isn't married to his teammates asserts nothing new once homogeneity is accommodated.

        theorem GuerriniWehbe2025.judgments_13 :
        (Examples.ex_13a.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w.card ≤ 1} fun (w : Finset (Fin 2)) => SignType.ofProp (w = ∅)) ∧ (Examples.ex_13b.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w.card ≤ 1} fun (w : Finset (Fin 2)) => SignType.ofProp (∀ (a : Fin 2), a ∉ w)) ∧ (Examples.ex_13c.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w.card ≤ 1} (-pexPlural Finset.univ Finset.univ BarLev2021.holds (supClosure (Set.range (BarLev2021.atom BarLev2021.holds))))) ∧ (Examples.ex_13d.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 2) | w.card ≤ 1} (pexPlural Finset.univ Finset.univ (fun (a : Fin 2) (w : Finset (Fin 2)) => a ∉ w) (supClosure (Set.range (BarLev2021.atom fun (a : Fin 2) (w : Finset (Fin 2)) => a ∉ w)))))

        In (13), where at most one candidate can win, none of the candidates won and all of the candidates lost are informative, but the candidates didn't win and the candidates lost assert nothing new once homogeneity is accommodated.

        theorem GuerriniWehbe2025.judgments_23 :
        Examples.ex_23.judgment = Judgment.acceptable ↔ Informative {w : Finset (Fin 3) | w ≠ Finset.univ} (-pexPlural Finset.univ Finset.univ BarLev2021.holds (supClosure (Set.range (BarLev2021.atom BarLev2021.holds))))

        In (23), with the students known not to have all smiled, the students didn't smile asserts nothing new once homogeneity is accommodated.