Documentation

Studies.Wang2025

Wang (2025): Presupposition, Competition, and Coherence #

Wang's dissertation explains when a presupposition trigger of Mandarin is obligatory and when it is dropped by a competition between the presuppositional sentence and its non-presuppositional alternative, a sentence with the same assertion that is obtained by deleting or replacing the trigger. Three constraints decide the competition, ranked in this order. Internal Coherence requires the utterance to be consistent with the common ground, Felicity Presupposition requires a presupposition to be entailed by it, and Maximize Presupposition, after Heim, bars a form that has a presuppositionally stronger alternative. An utterance commits the speaker to a set of information states and a context admits a set of them, so coherence is overlap, and the context entails a proposition when every state it admits believes the proposition.

Main statements #

Implementation notes #

References #

Information states, commitments and contexts #

def Wang2025.K {W : Type u_1} (p : Set W) :
Set (Set W)

K p is the set of nonempty information states included in p, those in which the speaker believes p.

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  • Wang2025.K p = {s : Set W | s.Nonempty ∧ s ⊆ p}
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    def Wang2025.Poss {W : Type u_1} (p : Set W) :
    Set (Set W)

    Poss p is the set of states meeting p, those in which the speaker holds p possible.

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      def Wang2025.Ignorant {W : Type u_1} (p : Set W) :
      Set (Set W)

      Ignorant p is the set of states in which p and its negation are both possible.

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        structure Wang2025.Candidate (W : Type u_2) :
        Type u_2

        A candidate is an utterance in the competition, given by the states its use commits the speaker to and by its presupposition if it has one.

        • commitment : Set (Set W)
        • presup : Option (Set W)
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          def Wang2025.presupSentence {W : Type u_1} (p a : Set W) :

          The presuppositional sentence with presupposition p and assertion a commits the speaker to both.

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            def Wang2025.plain {W : Type u_1} (a : Set W) :

            The unexhaustified non-presuppositional alternative commits the speaker to a.

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              def Wang2025.plainExhBelowK {W : Type u_1} (a q : Set W) :

              The alternative exhaustified against q below the belief operator commits the speaker to a and to the negation of q.

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                def Wang2025.plainExhAboveK {W : Type u_1} (a q : Set W) :

                The alternative exhaustified against q above the belief operator commits the speaker to a while the speaker does not believe q.

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                  The constraints and their ranking, (3) #

                  def Wang2025.ViolIC {W : Type u_1} (ctx : Set (Set W)) (c : Candidate W) :

                  Internal Coherence is violated when the commitment excludes every admissible state.

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                    def Wang2025.ViolFP {W : Type u_1} (ctx : Set (Set W)) (c : Candidate W) :

                    Felicity Presupposition is violated by a presuppositional sentence whose presupposition the context does not entail.

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                      def Wang2025.Candidate.admits {W : Type u_1} (c : Candidate W) :
                      Set (Set (Set W))

                      A context admits a candidate when every admissible state believes its presupposition, if it has one.

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                        theorem Wang2025.Candidate.admits_of_presup_none {W : Type u_1} {c : Candidate W} (h : c.presup = none) :
                        c.admits = Set.univ
                        theorem Wang2025.Candidate.admits_of_presup_some {W : Type u_1} {c : Candidate W} {p : Set W} (h : c.presup = some p) :
                        c.admits = {ctx : Set (Set W) | ctx ⊆ K p}
                        theorem Wang2025.Candidate.admits_ssubset_univ {W : Type u_1} {c : Candidate W} {p : Set W} (h : c.presup = some p) :
                        c.admits ⊂ Set.univ

                        A presuppositional candidate is admitted by fewer contexts than a plain one, since the context {∅} admits no presupposition.

                        def Wang2025.ViolMP {W : Type u_1} (rival c : Candidate W) :

                        Maximize Presupposition is violated by a candidate that its rival blocks, the rival being presuppositionally stronger, admitted by strictly fewer contexts, (3c).

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                          theorem Wang2025.violMP_iff {W : Type u_1} {rival c : Candidate W} :
                          ViolMP rival c ↔ rival.admits ⊂ c.admits
                          theorem Wang2025.violMP_of_presup_none {W : Type u_1} {rival c : Candidate W} {p : Set W} (hc : c.presup = none) (hr : rival.presup = some p) :
                          ViolMP rival c

                          A candidate without a presupposition violates Maximize Presupposition against a presuppositional rival, whatever the context.

                          theorem Wang2025.not_violMP_self {W : Type u_1} (c : Candidate W) :
                          ¬ViolMP c c
                          def Wang2025.Beats {W : Type u_1} :
                          List (Candidate W → Prop) → Candidate W → Candidate W → Prop

                          Beats cs a b compares two candidates by strict domination along the list cs of violation predicates, a beating b at the first constraint on which they differ.

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                            def Wang2025.ranking {W : Type u_1} (ctx : Set (Set W)) (sp : Candidate W) :
                            List (Candidate W → Prop)

                            The ranking Internal Coherence ≫ Felicity Presupposition ≫ Maximize Presupposition, evaluated for the competition between sp and its alternative.

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                              theorem Wang2025.violFP_presupSentence {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} :
                              ViolFP ctx (presupSentence p a) ↔ ¬ctx ⊆ K p

                              A presuppositional sentence violates Felicity Presupposition exactly when the context does not entail its presupposition. A trigger without an alternative, such as jiu 'only', enters no competition, so this alone bars it from every context short of entailing the presupposition.

                              The three decisive facts #

                              theorem Wang2025.presup_beats_of_incoherent {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} {c : Candidate W} (hsp : ¬Disjoint ctx (K (p ∩ a))) (hc : Disjoint ctx c.commitment) :

                              A coherent presuppositional sentence beats an incoherent alternative.

                              theorem Wang2025.plain_beats_of_not_entailed {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} {c : Candidate W} (hc0 : c.presup = none) (hsp : ¬Disjoint ctx (K (p ∩ a))) (hc : ¬Disjoint ctx c.commitment) (hp : ¬ctx ⊆ K p) :

                              A coherent alternative beats a presuppositional sentence whose presupposition is not entailed, when both are coherent.

                              theorem Wang2025.presup_beats_of_entailed {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} {c : Candidate W} (hc0 : c.presup = none) (hsp : ¬Disjoint ctx (K (p ∩ a))) (hc : ¬Disjoint ctx c.commitment) (hp : ctx ⊆ K p) :

                              A presuppositional sentence whose presupposition is entailed beats a coherent non-presuppositional alternative.

                              Felicity Presupposition above Maximize Presupposition #

                              theorem Wang2025.presup_beats_of_mp_over_fp {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} {c : Candidate W} (hc0 : c.presup = none) (hsp : ¬Disjoint ctx (K (p ∩ a))) (hc : ¬Disjoint ctx c.commitment) :

                              Were Maximize Presupposition ranked above Felicity Presupposition, a coherent presuppositional sentence would beat a coherent alternative whatever the context entails, so every trigger with an alternative would be obligatory.

                              The tableaux #

                              theorem Wang2025.obligatory_of_entailed {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hp : ctx ⊆ K p) (hwit : ∃ s ∈ ctx, s ⊆ a) :

                              In Table 4.2 the context entails the presupposition, so the trigger is obligatory.

                              theorem Wang2025.omitted_of_not_entailed {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hp : ¬ctx ⊆ K p) (hwit : ∃ s ∈ ctx, s.Nonempty ∧ s ⊆ p ∩ a) :

                              In Table 4.3 the context does not entail the presupposition, so the trigger is dropped.

                              theorem Wang2025.obligatory_of_positive_evidence {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hposs : ctx ⊆ Poss p) (hwit : ∃ s ∈ ctx, s.Nonempty ∧ s ⊆ p ∩ a) :

                              In Table 4.4, with positive evidence for the presupposition and the alternative exhaustified below the belief operator, the exhaustive implicature contradicts the context and the trigger is obligatory, although its presupposition is not entailed.

                              theorem Wang2025.omitted_of_denied {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hneg : ctx ⊆ K pᶜ) (hwit : ∃ s ∈ ctx, s ⊆ a) :

                              In Table 4.5 the context denies the presupposition, so the presuppositional sentence is incoherent and the alternative wins.

                              theorem Wang2025.omitted_of_ignorance {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hign : ctx ⊆ Ignorant p) (hwit : ∃ s ∈ ctx, s ⊆ a) :

                              In Table 4.6, an ignorance context with the alternative exhaustified above the belief operator, the presuppositional sentence commits the speaker to the presupposition and so contradicts the ignorance, while the alternative is coherent; the trigger is dropped.

                              theorem Wang2025.optional_of_two_readings {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hposs : ctx ⊆ Poss p) (hp : ¬ctx ⊆ K p) (hwit : ∃ s ∈ ctx, s.Nonempty ∧ s ⊆ p ∩ a) :

                              In Tables 4.7 and 4.9 the context gives positive evidence for the presupposition without entailing it, and the alternative has two exhaustified readings. Exhaustified against the failure of the presupposition, so that it conveys that the presupposition holds, the alternative wins. Exhaustified against the presupposition, it loses, so the trigger is optional.

                              theorem Wang2025.obligatory_of_entailed_of_two_readings {W : Type u_1} {ctx : Set (Set W)} {p a : Set W} (hp : ctx ⊆ K p) (hwit : ∃ s ∈ ctx, s ⊆ a) :

                              In Tables 4.8 and 4.10 the context entails the presupposition, and the trigger wins on both readings of the alternative.

                              The alternative structure of the triggers, Table 4.1 #

                              A trigger's non-presuppositional alternative is obtained by deleting the trigger, by replacing it, or not at all.

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                                  The lexical triggers of Table 4.1 are the adverbs ye 'also', fan'er 'instead', reng 'still', you and zai 'again', buzai 'no longer' and jiu 'only', and the verbs kaishi 'start', zhidao 'know' and houhui 'regret'.

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                                    def Wang2025.instReprTrigger.repr :
                                    Trigger → ℕ → Std.Format
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                                      @[instance_reducible]
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                                      theorem Wang2025.isTrigger_of_entry {t : Trigger} {v : Mandarin.Verb} (h : t.entry = Sum.inr v) :

                                      The verbal triggers are presupposition triggers by their fragment entries.

                                      The replacement for zhidao is non-presuppositional, as (1) requires, since renwei 'believe' is not a trigger.

                                      The aspectual triggers #

                                      The repetitive you and zai, (12), the continuative reng, (24), the inchoative kaishi, (38), and the cessative buzai, (19), relate their prejacent at the index of evaluation to the prejacent at an earlier index, presupposing that it held or failed then and asserting that it holds or fails now.

                                      def Wang2025.Candidate.ofTrivalent {W : Type u_1} (φ : W → SignType) :

                                      The candidate for a sentence with the trivalent meaning φ commits the speaker to its presupposition, where φ is defined, and to its assertion, where φ is true.

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                                        theorem Wang2025.Candidate.ofTrivalent_eq_presupSentence {W : Type u_1} {φ : W → SignType} {a : Set W} (h : ∀ (w : W), φ w ≠ 0 → (φ w = 1 ↔ w ∈ a)) :
                                        ofTrivalent φ = presupSentence (Function.support φ) a

                                        A sentence that asserts a wherever its meaning is defined is the presuppositional sentence with that presupposition and the assertion a.

                                        noncomputable def Wang2025.Trigger.aspectual {W : Type u_1} (R S : SetRel W W) (P : W → Prop) :
                                        Trigger → Option (W → SignType)

                                        The meaning of an aspectual trigger with the prejacent P. R relates an index to the earlier ones, the < of (12), and S relates an index to the earlier index of (19), (24) and (38), a relation the dissertation writes ∞. The meaning of kaishi is that of the phasal class of its fragment entry, and the other triggers of Table 4.1 are not aspectual.

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                                          theorem Wang2025.eq_one_iff_of_altStructure_deletion {W : Type u_1} {R S : SetRel W W} {P : W → Prop} {t : Trigger} {φ : W → SignType} (h : Trigger.aspectual R S P t = some φ) (ht : t.altStructure = AltStructure.deletion) {w : W} (hw : φ w ≠ 0) :
                                          φ w = 1 ↔ P w

                                          An aspectual trigger whose alternative is obtained by deletion asserts its prejacent, so the sentence without the trigger makes the same assertion, as (1) requires of the alternative.

                                          theorem Wang2025.eq_one_iff_buzai {W : Type u_1} {R S : SetRel W W} {P : W → Prop} {φ : W → SignType} (h : Trigger.aspectual R S P Trigger.buzai = some φ) {w : W} (hw : φ w ≠ 0) :
                                          φ w = 1 ↔ ¬P w

                                          Buzai asserts the negation of its prejacent, so its alternative replaces it by negation.

                                          theorem Wang2025.aspectual_obligatory_of_entailed {W : Type u_1} {R S : SetRel W W} {P : W → Prop} {ctx : Set (Set W)} {t : Trigger} {φ : W → SignType} (h : Trigger.aspectual R S P t = some φ) (ht : t.altStructure = AltStructure.deletion) (hp : ctx ⊆ K (Function.support φ)) (hwit : ∃ s ∈ ctx, s ⊆ {w : W | P w}) :

                                          A sentence with an aspectual trigger that asserts its prejacent is obligatory, against the sentence without the trigger, when the context entails its presupposition, as in Table 4.2.

                                          theorem Wang2025.aspectual_omitted_of_not_entailed {W : Type u_1} {R S : SetRel W W} {P : W → Prop} {ctx : Set (Set W)} {t : Trigger} {φ : W → SignType} (h : Trigger.aspectual R S P t = some φ) (ht : t.altStructure = AltStructure.deletion) (hp : ¬ctx ⊆ K (Function.support φ)) (hwit : ∃ s ∈ ctx, s.Nonempty ∧ s ⊆ Function.support φ ∩ {w : W | P w}) :

                                          A sentence with an aspectual trigger that asserts its prejacent loses to the sentence without the trigger when the context does not entail its presupposition, as in Table 4.3.

                                          Exhaustification by maximal consistent subsets, (20) and (24) #

                                          def Wang2025.exhMx {W : Type u_1} [DecidableEq W] (φ : Finset W) (M : Finset (Finset W)) :
                                          Finset W

                                          The reading of (24) for the maximal subset M is φ with every member of M negated.

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                                            theorem Wang2025.exhIE_eq_exhMx_of_unique {W : Type u_1} [DecidableEq W] {φ : Finset W} {alts M₀ : Finset (Finset W)} (h₀ : Exhaustification.IsMaximalExclusion alts φ M₀) (huniq : ∀ (M : Finset (Finset W)), Exhaustification.IsMaximalExclusion alts φ M → M = M₀) :

                                            When the maximal consistent subset is unique, innocent exclusion, the operator of (20), and the operator of (24) agree, (25).

                                            @[reducible, inline]

                                            The worlds of the disjunction example (26) are the pairs of truth values of p and q.

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                                              def Wang2025.pAlt :
                                              Finset PQ

                                              The alternative p of (26).

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                                                def Wang2025.qAlt :
                                                Finset PQ

                                                The alternative q of (26).

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                                                  The disjunction p ∨ q with the alternatives p, q and p ∧ q, (26), has two maximal consistent subsets, yielding the readings q ∧ ¬p and p ∧ ¬q.

                                                  def Wang2025.cell (past now : Bool) :
                                                  Finset PQ

                                                  The cell of (48) in which the state held in the past iff past and holds now iff now, a world being the pair of the two truth values.

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                                                    def Wang2025.cells :
                                                    Finset (Finset PQ)

                                                    The alternatives of (48), the four cells.

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                                                      def Wang2025.notNow :
                                                      Finset PQ

                                                      The prejacent of (46), that the state does not hold now, the alternative of a sentence with buzai 'no longer'.

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                                                        theorem Wang2025.notNow_two_maxima :
                                                        Exhaustification.IsMaximalExclusion cells notNow {cell false true, cell true true, cell false false} ∧ Exhaustification.IsMaximalExclusion cells notNow {cell false true, cell true false, cell true true} ∧ exhMx notNow {cell false true, cell true true, cell false false} = cell true false ∧ exhMx notNow {cell false true, cell true false, cell true true} = cell false false

                                                        The alternative of buzai has the two maximal consistent subsets of (49), on which it means that the state held in the past and that it did not.