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Linglib.Phenomena.FreeChoice.Studies.Alsop2024

@cite{alsop-2024} — Free Choice Any as GI-RSA #

@cite{alsop-2024} @cite{champollion-alsop-grosu-2019} @cite{franke-bergen-2020} @cite{tessler-franke-2019}

"Disjunction, Free Choice, and Exhaustification" (Chapter 4)

The Model #

Domain: "You may take any class" with 2 items {S, P}. 7 states based on permission structure (which baskets are permitted). 4 utterances. 2 global interpretation functions (weak/Szabolcsi vs strong/Dayal), following the GI-RSA architecture of @cite{franke-bergen-2020}.

Parameters: α = 2, uniform interpretation prior, configurable world prior.

Qualitative Findings #

#FindingTheorem
1Exclusiveness derivedexclusiveness_derived
2Exclusiveness robust to priorexclusiveness_robust
3Not-every holds under uniform priornot_every_uniform
4Not-every weakened under biased priornot_every_weakened
5Hearing "may S" → S is permittedliteral_s_correct
6Hearing "may every" → both permittedevery_permBoth
7Ambiguity essential for FCexclusiveness_requires_ambiguity
8No FC under negationno_fc_under_negation

The 7 states from @cite{alsop-2024} for a 2-item domain {S, P}. Each state is defined by which baskets are permitted: w0 (nothing), wS (S only), wP (P only), wSP (both).

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    def RSA.FCIAny.instReprFCIState.repr :
    FCIStateStd.Format
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      The 4 utterances.

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        def RSA.FCIAny.instReprUtterance.repr :
        UtteranceStd.Format
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          Two global interpretation functions (GI-RSA). Each assigns a meaning to every utterance simultaneously.

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            def RSA.FCIAny.instReprInterp.repr :
            InterpStd.Format
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              ◇take(S)_strict: taking S alone is a permitted basket (wS accessible).

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                ◇take(P)_strict: taking P alone is a permitted basket (wP accessible).

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                  ◇take(S)_liberal: S is obtainable (alone or via both).

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                    ◇take(P)_liberal: P is obtainable (alone or via both).

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                      Exclusiveness: each item is individually (strictly) permitted. ∀x[◇take(x)_strict]. True at {only1, anyNum}.

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                        Not-every: taking both is not permitted. ¬◇(S∧P). True at {onlyS, onlyP, only1}.

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                          Weak (Szabolcsi) interpretation: unexhaustified meanings.

                          • May S: ◇take(S)_liberal (6 states, all except onlyP)
                          • May P: ◇take(P)_liberal (6 states, all except onlyS)
                          • May Any: ∃x[◇take(x)] (7 states, always true)
                          • May Every: ◇take(S∧P) (4 states: anyNum, only2, sOrBoth, pOrBoth)
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                            Strong (Dayal) interpretation: exhaustified meanings.

                            • May S: {onlyS} (only S permitted, not P, not both)
                            • May P: {onlyP} (only P permitted, not S, not both)
                            • May Any: {only1, anyNum} (∀x[◇take(x)_strict], exclusiveness)
                            • May Every: {only2} (must take both, neither alone)
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                              The strong interpretation characterizes exclusiveness exactly.

                              The weak interpretation is always true for "may any".

                              Exclusiveness = ∀x[◇take(x)_strict].

                              Not-every = ¬permBoth.

                              theorem RSA.FCIAny.strong_refines_weak (u : Utterance) (w : FCIState) :
                              strongMeaning u w = trueweakMeaning u w = true

                              The strong interpretation refines the weak for all utterances.

                              Permission predicates correctly characterize key states.

                              noncomputable def RSA.FCIAny.cfg (worldPr : FCIState) (hp : ∀ (w : FCIState), 0 worldPr w) :

                              @cite{alsop-2024} GI-RSA model for free choice any. Two global interpretations serve as latent variables. S1 score is rpow(L0, α) — standard belief-based RSA.

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                                Uniform prior: all states equally likely.

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                                  Biased prior: P(anyNum) = 3, others = 1. Biases toward the state where exclusiveness holds but not-every does not, testing prior sensitivity of the two inferences.

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                                    Exclusiveness is derived: L1 assigns more mass to exclusiveness states than non-exclusiveness states upon hearing "may any".

                                    Exclusiveness is robust: holds even under a prior biased toward anyNum.

                                    Not-every is weakened under biased prior (prior-sensitive).

                                    Hearing "may S", the listener infers S is (strictly) permitted.

                                    Hearing "may every", the listener infers both are permitted.

                                    Counterfactual: both interpretations use weak meaning (no ambiguity). Without the informativity gap between weak (7 states for "may any") and strong (2 states), S1 cannot discriminate exclusiveness states.

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                                      Without interpretation ambiguity, exclusiveness is NOT derived. The informativity gap between weak (7 states) and strong (2 states) is what drives L1 toward exclusiveness states. Without a strong parse, "may any" is uninformative and the prior dominates: 2/7 exclusiveness states vs 5/7 non-exclusiveness states.

                                      Extended utterances including negation of "may any".

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                                          Weak meaning extended with negation. "May not any" under weak = ¬∃x[◇take(x)] = false everywhere, since the weak existential meaning is trivially true at all states.

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                                            RSAConfig for the extended model with negation.

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                                              Free choice does NOT emerge under negation. Under negation, the weak interpretation is vacuous (false everywhere) and the strong interpretation supports only non-exclusiveness states. The informativity gap that drives FC in the positive case disappears.

                                              The 8 qualitative findings from @cite{alsop-2024}.

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                                                def RSA.FCIAny.instReprFinding.repr :
                                                FindingStd.Format
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                                                  noncomputable def RSA.FCIAny.formalize :

                                                  Map each finding to its RSA formalization.

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                                                    The RSA model accounts for all 8 findings from @cite{alsop-2024}.

                                                    Bridge content (merged from RSA_Alsop2024Bridge.lean) #

                                                    Bridge: RSA Free Choice Any → Phenomena Data #

                                                    @cite{alsop-2024}

                                                    Connects the RSA free choice any model from @cite{alsop-2024} to empirical data in Phenomena.FreeChoice.

                                                    Bridge Theorems #

                                                    Connection to Phenomena #

                                                    The model predicts the patterns in Phenomena.FreeChoice:

                                                    1. FCI Any (anyClass, anyFruit):

                                                      • "You may take any class" → permission for each class specifically
                                                      • Derived: L1 assigns ~100% to exclusiveness states
                                                    2. Robustness to priors:

                                                      • Exclusiveness holds even with unfavorable priors
                                                      • Parallels FCI robustness in disjunction
                                                    3. Not-every is cancelable:

                                                      • "You may take any class (in fact, you must take all of them)"
                                                      • The "not every" inference can be cancelled, unlike exclusiveness

                                                    Free choice any is predicted for permission sentences

                                                    Exclusiveness is robust to priors (as recorded in the data)