Documentation

Linglib.Theories.Semantics.Degree.Frameworks.Klein

Klein's Delineation Approach #

@cite{burnett-2014} @cite{klein-1980} @cite{van-rooij-2011} @cite{kennedy-2007} @cite{kamp-1975}

@cite{klein-1980} "A Semantics for Positive and Comparative Adjectives": a degree-free analysis where gradable adjectives are simple predicates (type ⟨e,t⟩) whose extension is determined relative to a comparison class — a contextually supplied set of entities.

Lineage from Kamp (1975) #

Klein's comparative — ∃ C. tall(a,C) ∧ ¬tall(b,C) — is a direct formalization of @cite{kamp-1975}'s definition (12): u₁ is at least as A as u₂ iff in every completion where u₂ is in the extension, u₁ is too. Kamp's "completions" become Klein's "comparison classes"; both derive the comparative from existential quantification over ways of making a vague predicate precise.

Key Ideas #

  1. No degrees: "tall" does not denote a relation between entities and degrees. It is simply a predicate whose extension varies with context.

  2. Comparison class: The positive form "Kim is tall" is true iff Kim is tall relative to the contextually relevant comparison class C (e.g., basketball players, children, people in general).

  3. Comparative via supervaluation: "Kim is taller than Lee" is true iff there exists a comparison class C where Kim is tall and Lee is not. This uses a supervaluation over comparison classes rather than degree comparison.

Comparison with Kennedy #

Feature@cite{kennedy-2007}@cite{klein-1980}
OntologyDegrees existNo degrees
⟦tall⟧λd.λx. height(x) ≥ dλx. tall(x) in C
Comparativemax > max∃C. tall(x) ∧ ¬tall(y)
VaguenessThreshold variabilityComparison class var.
Measure phrasesDirect (3 inches of d)Requires extension

Klein's approach has difficulty with measure phrases ("3 inches taller") and degree modifiers ("very tall"), which are natural in degree-based frameworks.

A comparison class: a set of entities relevant for evaluating a gradable predicate. In Klein's framework, this is the only contextual parameter — there are no degrees or thresholds.

Equations
Instances For
    def Semantics.Degree.Frameworks.Klein.positiveSem {Entity : Type u_1} (delineation : ComparisonClass EntityEntityProp) (C : ComparisonClass Entity) (x : Entity) :

    Klein's positive form: "Kim is tall" is true iff Kim is in the positive extension of "tall" relative to comparison class C.

    The delineation function partitions entities in C into those that satisfy the predicate and those that don't. The partition can be indeterminate (vagueness = gap between positive and negative extension).

    Equations
    Instances For
      def Semantics.Degree.Frameworks.Klein.comparativeSem {Entity : Type u_1} (delineation : ComparisonClass EntityEntityProp) (a b : Entity) :

      Klein's comparative: "Kim is taller than Lee" is true iff there EXISTS a comparison class C such that Kim is tall-in-C but Lee is not tall-in-C.

      This is a supervaluation over comparison classes: the comparative holds when the predicate can discriminate the two entities.

      Equations
      Instances For
        def Semantics.Degree.Frameworks.Klein.IsMonotoneDelineation {Entity : Type u_1} (delineation : ComparisonClass EntityEntityProp) (allClasses : Set (ComparisonClass Entity)) :

        Klein's comparative is asymmetric: if a is taller than b, then b is not taller than a.

        This requires the monotonicity constraint on delineations: if a is tall-in-C and b is not, then for any C' where b is tall, a is also tall. Without this constraint, the comparative can fail to be asymmetric.

        Equations
        • One or more equations did not get rendered due to their size.
        Instances For

          @cite{klein-1980}'s comparative is the existential dual of @cite{fine-1975}'s supervaluation. Where supervaluation asks "true at ALL specifications?", Klein asks "true at SOME specification where the other is false?" Both quantify over the same space — comparison classes (Klein) = specification points (Fine). The positive form "a is tall" maps to superTrue (delineation · a), and Klein's comparative ∃ C. tall(a,C) ∧ ¬tall(b,C) captures the asymmetry between a's and b's supervaluation status.

          Under monotone delineation, Klein's comparative entails Fine's
          comparative entailment: if b is super-true (tall in every comparison
          class), then a — who is at least as tall — must also be super-true. 
          
          theorem Semantics.Degree.Frameworks.Klein.monotone_comparative_superTrue {Entity : Type u_1} (delineation : ComparisonClass EntityEntityProp) [(C : ComparisonClass Entity) → (x : Entity) → Decidable (delineation C x)] (a b : Entity) (S : Supervaluation.SpecSpace (ComparisonClass Entity)) (hmono : C₁S.admissible, C₂S.admissible, ∀ (x y : Entity), delineation C₁ x¬delineation C₁ ydelineation C₂ ydelineation C₂ x) (hdisc : CS.admissible, delineation C a ¬delineation C b) (hb : Supervaluation.superTrue (fun (C : ComparisonClass Entity) => decide (delineation C b)) S = Core.Duality.Truth3.true) :

          Under monotone delineation, Klein's comparative entails Fine's comparative entailment: if b is super-true, a is super-true.

          The proof extracts the discriminating comparison class C₀ (where a is tall but b isn't), then uses monotonicity: in any class C₂ where b is tall, a must also be tall.

          theorem Semantics.Degree.Frameworks.Klein.comparative_prevents_superTrue {Entity : Type u_1} (delineation : ComparisonClass EntityEntityProp) [(C : ComparisonClass Entity) → (x : Entity) → Decidable (delineation C x)] (a b : Entity) (S : Supervaluation.SpecSpace (ComparisonClass Entity)) (hdisc : CS.admissible, delineation C a ¬delineation C b) :

          Klein's comparative witnesses supervaluation indefiniteness for b: if a is taller than b (∃ discriminating class IN the space), then b is not super-true — the discriminating class falsifies b.