Cooper (2023) Ch. 7 β Witness-based Quantification #
@cite{cooper-2023} @cite{barwise-cooper-1981} @cite{van-benthem-1984}
@cite{cooper-2023} Chapter 7 replaces classical set-theoretic GQ denotations
(cf. Core.Quantification.GQ) with witness sets β finite sets of
individuals satisfying cardinality conditions specific to each quantifier.
This study formalises Ch. 7 directly. It was formerly substrate at
Theories/Semantics/TypeTheoretic/Quantification.lean but is genuinely
a single-paper Cooper-textbook replication: only LuckingGinzburg2022
and Phenomena/Anaphora/Studies/Cooper2023 consume it externally, and
both are themselves Cooper-2023-anchored discussions.
Key contributions:
- π(P): the type whose witnesses are P-individuals (Β§7.2.3)
- π/πΚΈ: purification operators extracting pure properties (Β§7.2.3)
- qΚ·(P): witness set types per quantifier (Β§7.2.4)
- Austinian propositions (π): probabilistic quantification (Β§7.3)
- General vs particular witness conditions: predict anaphora (Β§7.4)
- Complement witness sets: COMPSET anaphora for 'few' (Β§7.4)
- Contexts with gaps: long distance dependencies (Β§7.5)
Β§7.2.3 Pure properties, purification, and π(P) (eqs 11β19) #
A parametric property P : PPpty E has background P.Bg and foreground P.fg. P is pure when Bg is trivial (β Unit): no extra background constraints.
Purification folds background conditions into the property body:
- π(P): existential β β context satisfying bg, body holds (weak donkey)
- πΚΈ(P): universal β β contexts satisfying bg, body holds (strong donkey)
A parametric property is pure when its background is trivial. Β§7.2.3, eq (7a): P.bg has only the x-field.
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- Phenomena.Quantification.Studies.Cooper2023.PPpty.isPure P = (Nonempty P.Bg β§ Subsingleton P.Bg)
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The type of witnesses for property P. Β§7.2.3, eq (17): a : π(P) iff π(P){a} is witnessed. For a pure property, π(P) = {a : E // Nonempty (P a)}.
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- Phenomena.Quantification.Studies.Cooper2023.WitnessType P = { a : E // Nonempty (P a) }
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Existential purification of a parametric property. Β§7.2.3, eq (12): π(P) merges background conditions into the body via existential quantification. π(P)(a) = Ξ£ (c : Bg), fg c a.
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- Phenomena.Quantification.Studies.Cooper2023.purify P a = ((c : P.Bg) Γ P.fg c a)
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Universal purification of a parametric property. Β§7.2.3, eq (13): πΚΈ(P) universally quantifies over background contexts. Used for strong donkey readings.
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- Phenomena.Quantification.Studies.Cooper2023.purifyUniv P a = ((c : P.Bg) β P.fg c a)
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Notation for purification operators.
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For a trivial parametric property, purification adds only a Unit factor.
Purified property is witnessed iff the original is witnessable under some context.
Universal purification: witnessed iff property holds under all contexts.
WitnessType for parametric properties via purification.
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Β§7.2.4 Types of witness sets for quantifiers (eqs 20β35) #
Each quantifier q defines a type qΚ·(P) of witness sets. X : qΚ·(P) iff (1) X β extension of P, and (2) a cardinality condition.
All witness set types share a common subset condition (X β [βP]).
This structural requirement is what derives conservativity from the
witness architecture β it's not stipulated as in @cite{barwise-cooper-1981}.
Computable extension of P as a Finset. Cooper's [π(P)] or [βP].
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- Phenomena.Quantification.Studies.Cooper2023.fullExtFinset P = Finset.filter P Finset.univ
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Base witness set condition: X β extension of P. Β§7.2.4: every witness set type requires this.
- subset (a : E) : a β X β P a
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existΚ·(P): singleton witness set. Eq (21).
- card_eq : X.card = 1
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exist_plΚ·(P): plural some, |X| β₯ 2. Eq (22).
- card_ge : X.card β₯ 2
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noΚ·(P): empty set. Eqs (23β24).
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- Phenomena.Quantification.Studies.Cooper2023.IsNoW _P X = (X = β )
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everyΚ·(P): the full extension. Eqs (25β26).
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mostΚ·(P): proportional, |X|/|[βP]| β₯ ΞΈ. Eq (29). Stated as cross-multiplication: X.card * denom β₯ num * ext.card.
- extPos : (fullExtFinset P).card > 0
- proportion : X.card * ΞΈ_denom β₯ ΞΈ_num * (fullExtFinset P).card
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many_aΚ·(P): absolute threshold, |X| β₯ ΞΈ. Eq (30).
- card_ge : X.card β₯ ΞΈ
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many_pΚ·(P): proportional, |X|/|[βP]| β₯ ΞΈ. Eq (31).
- extPos : (fullExtFinset P).card > 0
- proportion : X.card * ΞΈ_denom β₯ ΞΈ_num * (fullExtFinset P).card
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few_aΚ·(P): absolute, |X| β€ ΞΈ. Eq (32).
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few_pΚ·(P): proportional, |X|/|[βP]| β€ ΞΈ. Eq (33).
- extPos : (fullExtFinset P).card > 0
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a_few_aΚ·(P): absolute, |X| β₯ ΞΈ (same threshold as few, reversed direction). Eq (34).
- card_ge : X.card β₯ ΞΈ
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a_few_pΚ·(P): proportional, |X|/|[βP]| β₯ ΞΈ. Eq (35).
- extPos : (fullExtFinset P).card > 0
- proportion : X.card * ΞΈ_denom β₯ ΞΈ_num * (fullExtFinset P).card
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Complement witness set for few (absolute). Eq (81). XΜ : fewΜΚ·_a(P) iff |X| β₯ |[π(P)]| β ΞΈ. Predicts COMPSET anaphora.
- card_ge : X.card β₯ (fullExtFinset P).card - ΞΈ
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Complement witness set for few (proportional). Eq (82).
- extPos : (fullExtFinset P).card > 0
- proportion : X.card * ΞΈ_denom β₯ (ΞΈ_denom - ΞΈ_num) * (fullExtFinset P).card
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noΚ· has exactly one witness set: β .
everyΚ· has exactly one witness set: the full extension.
Β§7.3 Austinian propositions and probabilistic quantification (eqs 36β58) #
Probabilities for quantifiers are estimated from an agent's finite experience base π β a set of Austinian propositions recording categorical judgments [sit=a, type=T].
Frequentist conditional probability: p_π(TββTβ) = |[Tββ§Tβ]_π| / |[Tβ]_π|
An experience base: the agent's memory of categorical judgments. Β§7.3, eq (37): π is a finite set of [sit=a, type=T] records. Parameterized over entity type E and predicate type P.
- judgments : Finset (E Γ P)
The observed entity-predicate judgments
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Extension of predicate p relative to π. Β§7.3, eq (38): [T]_π = {a | a :_π T}.
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Joint extension: entities classified under both predicates.
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Frequentist conditional probability estimate (as numerator/denominator). Β§7.3, eq (36): p_π(TββTβ) = |[Tββ§Tβ]_π| / |[Tβ]_π|.
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Reliability of a probability estimate (count before log). Β§7.3, eq (40): reliability = ln min(|[Tβ]_π|, |[Tβ]_π|).
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- π.reliability p q = min (π.ext p).card (π.ext q).card
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Β§7.4 Witness conditions for quantificational ptypes (eqs 59β90) #
The central theoretical contribution: how quantifiers evaluate. Each q(P,Q) is witnessed by a pair (X, f) where X is a witness set and f maps witnesses to Q-evidence.
Two patterns:
- General (eq 59): for all quantifiers, uses purified Q
- Particular (eq 63): simpler, only for some quantifiers, better anaphora predictions
General witness condition for monotone β quantifiers. Β§7.4, eq (59a): s : q(P,Q) iff s : [X : qΚ·(P), f : (a : π(X)) β π(Q){a}] Each member of X must individually witness Q.
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General witness condition for monotone β quantifiers. Β§7.4, eq (59b): Every entity with both P and Q lands in X.
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Particular witness condition for exist(P,Q). Eq (63). s : exist(P,Q) iff s : [x : π(P), e : π(Q){x}] The x-field enables REFSET (singular) anaphora: "A dog barked. It heard an intruder."
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Particular witness condition for no(P,Q). Eq (70). Every P-entity fails to have Q (type negation). everyΚ·(P) as witness set predicts MAXSET anaphora: "No dog barked. They (= the dogs) were all asleep."
- f (a : E) : β (aβ : P a), IsEmpty (Q a)
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Particular witness condition for few with complement. Eqs (85β86). Uses complement witness set: P-entities lacking Q. Predicts COMPSET anaphora: "Few dogs barked. They (= non-barking dogs) slept through."
- X : Finset E
- allP (a : E) : a β self.X β Nonempty (P a)
- allNotQ (a : E) : a β self.X β IsEmpty (Q a)
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The particular exist condition implies the general one (with singleton X). Β§7.4: the particular condition "provides a component in the witness (in the 'x'-field) which can be picked up on by singular anaphora."
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Anaphora set predictions per quantifier. Β§7.4.1: witness structure determines available anaphora.
- refset : AnaphoraRef
REFSET: reference to the witness individual/set. "A dog barked. It (= that dog) heard an intruder."
- maxset : AnaphoraRef
MAXSET: reference to the full extension. "Every dog barked. They (= the dogs) heard an intruder."
- compset : AnaphoraRef
COMPSET: reference to the complement witness set (for few). "Few dogs barked. They (= the non-barking dogs) slept through."
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- Phenomena.Quantification.Studies.Cooper2023.instDecidableEqAnaphoraRef xβ yβ = if h : xβ.ctorIdx = yβ.ctorIdx then isTrue β― else isFalse β―
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- Phenomena.Quantification.Studies.Cooper2023.instDecidableEqQuantName xβ yβ = if h : xβ.ctorIdx = yβ.ctorIdx then isTrue β― else isFalse β―
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Which anaphora sets each quantifier makes available. Β§7.4.1: summary table.
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- Phenomena.Quantification.Studies.Cooper2023.anaphoraAvailable Phenomena.Quantification.Studies.Cooper2023.QuantName.exist = [Phenomena.Quantification.Studies.Cooper2023.AnaphoraRef.refset]
- Phenomena.Quantification.Studies.Cooper2023.anaphoraAvailable Phenomena.Quantification.Studies.Cooper2023.QuantName.no = [Phenomena.Quantification.Studies.Cooper2023.AnaphoraRef.maxset]
- Phenomena.Quantification.Studies.Cooper2023.anaphoraAvailable Phenomena.Quantification.Studies.Cooper2023.QuantName.every = [Phenomena.Quantification.Studies.Cooper2023.AnaphoraRef.maxset]
- Phenomena.Quantification.Studies.Cooper2023.anaphoraAvailable Phenomena.Quantification.Studies.Cooper2023.QuantName.most = [Phenomena.Quantification.Studies.Cooper2023.AnaphoraRef.maxset]
- Phenomena.Quantification.Studies.Cooper2023.anaphoraAvailable Phenomena.Quantification.Studies.Cooper2023.QuantName.many = [Phenomena.Quantification.Studies.Cooper2023.AnaphoraRef.maxset]
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Β§7.5 Long distance dependencies (eqs 114β158) #
Cooper extends contexts with gap and wh-assignments to handle extraction, relative clauses, and wh-questions.
Context with gap assignment. Β§7.5: Cntxt = [π°, π€, π ] (the 3-field gap-aware context Cooper introduces around the slash-category discussion).
- π° : AssgnType
- π€ : AssgnType
- π : CntxtType
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Full context with wh- and gap assignments. Β§7.5: Cntxt = [π°, π΄, π€, π ] (the 4-field context for wh-extraction; Cooper's Ch. 8 eq (10) extends this to the 5-field {q, π°, π΄, π€, π }).
- π° : AssgnType
- π΄ : AssgnType
- π€ : AssgnType
- π : CntxtType
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Slash category: S/i is a sentence missing constituent at gap i. Β§7.5, eq (149): the TTR analogue of slash categories.
- mother : String
- gapIdx : β
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WhNP condition. Β§7.5, eq (149a): Ο : WhNP iff Ο : NP and Ξ©.bg β [π΄:[xα΅’:Ind]] for some i.
- whIdx : β
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Property conjunction. Β§7.5, eq (153): Pβ & Pβ for relative clauses. "child who Sam hugged" = child β§ hugged-by-Sam.
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- Phenomena.Quantification.Studies.Cooper2023.pptyConj Pβ Pβ x = (Pβ x Γ Pβ x)
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Property conjunction preserves witnesses.
Type-indexed property: properties of objects of type T. Β§7.5, eq (152): P : α΅Ppty iff P.bg β [x:T].
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Type-indexed parametric property.
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Phenomena #
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- Phenomena.Quantification.Studies.Cooper2023.instDecidableEqDogWorld xβ yβ = if h : xβ.ctorIdx = yβ.ctorIdx then isTrue β― else isFalse β―
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Dog property.
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- Phenomena.Quantification.Studies.Cooper2023.isDog Phenomena.Quantification.Studies.Cooper2023.DogWorld.fido = True
- Phenomena.Quantification.Studies.Cooper2023.isDog Phenomena.Quantification.Studies.Cooper2023.DogWorld.rex = True
- Phenomena.Quantification.Studies.Cooper2023.isDog Phenomena.Quantification.Studies.Cooper2023.DogWorld.spot = True
- Phenomena.Quantification.Studies.Cooper2023.isDog Phenomena.Quantification.Studies.Cooper2023.DogWorld.luna = False
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Bark property.
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- Phenomena.Quantification.Studies.Cooper2023.doesBark Phenomena.Quantification.Studies.Cooper2023.DogWorld.fido = True
- Phenomena.Quantification.Studies.Cooper2023.doesBark Phenomena.Quantification.Studies.Cooper2023.DogWorld.rex = False
- Phenomena.Quantification.Studies.Cooper2023.doesBark Phenomena.Quantification.Studies.Cooper2023.DogWorld.spot = True
- Phenomena.Quantification.Studies.Cooper2023.doesBark Phenomena.Quantification.Studies.Cooper2023.DogWorld.luna = False
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The full extension of isDog is {fido, rex, spot}.
Particular witness for "a dog barks": fido barks and is a dog.
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- Phenomena.Quantification.Studies.Cooper2023.aDogBarks = { x := Phenomena.Quantification.Studies.Cooper2023.DogWorld.fido, pWit := { down := trivial }, qWit := { down := trivial } }
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"No dog barks" fails: fido is a dog that barks.
few predicts COMPSET; a_few does not.
Predicate type for the dog example.
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- Phenomena.Quantification.Studies.Cooper2023.instDecidableEqDogPred xβ yβ = if h : xβ.ctorIdx = yβ.ctorIdx then isTrue β― else isFalse β―
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Simple experience base: 3 dogs observed, 2 bark.
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Two of three dogs bark: p(barkβdog) = 2/3.
Structural theorems #
Key theoretical claims of Ch 7, connecting witness-based quantification to classical GQ properties and each other.
Bridge: witness-based β GQ #
Every witness set type induces a classical GQ by existentially quantifying over witness sets. This is the fundamental connection between Cooper's type-theoretic quantifiers and Barwise & Cooper's set-theoretic ones.
The GQ induced by existential witness sets. exist(A,B) iff some element satisfies both A and B.
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- Phenomena.Quantification.Studies.Cooper2023.witnessGQ_exist A B = β (x : E), A x β§ B x
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The GQ induced by universal witness sets. every(A,B) iff every A-element also satisfies B.
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- Phenomena.Quantification.Studies.Cooper2023.witnessGQ_every A B = β (x : E), A x β B x
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Conservativity from witness structure #
All witness set types require X β [βP] (the subset condition). This structurally entails conservativity: q(P,Q) depends only on P β© Q, never on Q outside P. Β§7.2.4.
This is significant because conservativity is stipulated as an axiom in @cite{barwise-cooper-1981} but derived from the witness architecture.
Conservativity of witnessGQ_exist: follows from the subset condition in IsExistW. Cooper's key argument: conservativity is structural, not stipulated.
Conservativity of witnessGQ_every.
Bridge: witness quantification β extensional truth #
Cooper's witness-based quantifiers (type-theoretic) compute the same truth values as the extensional denotations in Semantics.Montague/Quantifier. This bridges the three layers of quantification: Core.Quantification (logical properties) β proved via conservativity above Semantics.Montague (extensional denotations) β proved via equivalence below TTR (witness-based) β definitions above
TTR's structured particular witness condition is equivalent to the
existential GQ being true. This is the key grounding theorem:
ParticularWC_Exist P Q is inhabited iff witnessGQ_exist holds.
The universal condition is equivalent to the universal GQ being true.
TTR's ParticularWC_Exist gives a constructive witness for the existential GQ.
TTR's ParticularWC_No implies the universal GQ with negated scope.
Purification and donkey anaphora #
Existential purification π gives weak donkey readings; universal purification πΚΈ gives strong donkey readings. For pure properties (trivial Bg), both collapse to identity.
Purification of a pure property is equivalent to the original. Β§7.2.3: if P.Bg β Unit, then π(P) β P.fg.
Universal purification of a pure property also collapses.
For pure properties, weak and strong donkey readings agree. Β§7.2.3: the distinction only matters when Bg is non-trivial.
Particular β general witness condition lifting #
Each particular witness condition implies the corresponding general one. The particular conditions are preferred because they expose finer-grained structure for anaphora resolution.
Particular no implies general (decreasing) no. Β§7.4, eqs (70) β (59b): if every P-entity lacks Q, then the empty witness set satisfies the decreasing condition (vacuously: no entity has both P and Q).
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- Phenomena.Quantification.Studies.Cooper2023.particular_no_implies_general P Q h Pd = { X := β , witnessOK := β―, f := β― }
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Complement witness sets and the few/a_few contrast #
Cooper's key empirical claim (Β§7.4.2): few and a_few share the same
cardinality threshold but differ in anaphora predictions because few
(downward monotone) supports complement witness sets while a_few
(upward monotone) does not.
- "Few dogs barked. They slept through." β they = non-barking dogs (COMPSET)
- "A few dogs barked. They heard the noise." β they = barking dogs (REFSET)
The complement witness set for few satisfies the complement
cardinality condition.
Β§7.4.2, eq (81): XΜ = π(P) \ X.
few_a and its complement partition the full extension. Β§7.4.2: X βͺ XΜ = π(P).
Record path subtraction (β) for LDD #
Β§7.5, eq (118): T β Ο removes a field from a record type. This is the operation underlying gap-threading: a transitive verb type minus its object field yields the gap-containing type.
Record path subtraction: remove a named field from a record. Β§7.5, eq (118): T β Ο removes field Ο from T. Encoded as filtering on a list of (label, type) pairs.
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- Phenomena.Quantification.Studies.Cooper2023.recSubtract fields path = List.filter (fun (p : String Γ Type) => decide (p.1 β path)) fields
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Subtraction removes exactly the targeted field.
Subtraction preserves other fields.
Dependency families and generalization (T^Ο) #
Β§7.5, eq (133): T^Ο = Ξ»v.[T β Ο β§ {Ο : v}]. A dependency family abstracts over the gap, yielding a function from entities to record types. This is the TTR analogue of lambda-abstraction over a trace in transformational grammar.
Dependency family: abstract over a gap to get a property. Β§7.5, eq (133): T^Ο(v) fills gap Ο with v.
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- Phenomena.Quantification.Studies.Cooper2023.dependencyFamily body P = ((a : E) Γ body a a Γ P a)
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Merging a dependency family with a quantifier yields a scope-taking constituent. Β§7.5, eq (137): "which child Sam hugged" = Quant derived from T^Ο.
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- Phenomena.Quantification.Studies.Cooper2023.depFamilyQuant body q = q fun (x : E) => (a : E) Γ body a x
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Monotonicity from witness conditions #
Β§7.4: the general witness condition for β quantifiers (59a) uses existential evidence per witness (f maps each to Q-evidence), while β quantifiers (59b) use universal containment (every Pβ§Q entity is in X). This structural difference predicts monotonicity direction.
Upward monotonicity of the increasing witness condition: if Q β Q' (at Type level), any witness for Q also witnesses Q'. Β§7.4, consequence of (59a).
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Downward monotonicity of the decreasing witness condition: if Q' β Q, then the decreasing condition on Q implies it on Q'. Β§7.4, consequence of (59b).
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- Phenomena.Quantification.Studies.Cooper2023.generalWC_decr_mono P Q Q' isWS embed w = { X := w.X, witnessOK := β―, f := β― }