Epistemic Entailment Patterns (@cite{holliday-icard-2013}, Figure 1) #
@cite{holliday-icard-2013} @cite{harrison-trainor-holliday-icard-2018} @cite{yalcin-2010}
@cite{holliday-icard-2013} Figure 1 lists 10 validity patterns (V1–V7, V11–V13)
and 3 invalidity patterns (I1–I3) for epistemic comparatives. (V8–V10 are from
@cite{yalcin-2010} and omitted from H&I's condensed figure.) This file defines
each pattern as a Prop-valued predicate on a comparison relation ge, then
proves which patterns hold (or fail) in each of three semantic classes:
| Pattern | Measure (FP∞) | Qualitative (FA) | l-lifting (W) | m-lifting |
|---|---|---|---|---|
| V1 | ✓ | ✓ | ✓ | ✓ |
| V2 | ✓ | ✓ | ✓ | ✓ |
| V3 | ✓ | ✓ | ✓ | ✓ |
| V4 | ✓ | ✓ | ✓ | ✓ |
| V5 | ✓ | ✓ | ✓ | ✓ |
| V6 | ✓ | ✓ | ✓ | ✓ |
| V7 | ✓ | ✓ | ✓ | ✓ |
| V11 | ✓ | ✓ | ✗ | ✓ |
| V12 | ✓ | ✓ | ✓ (preorder) | ✓ |
| V13 | ✓ | ✓ | ✗ | ✓ |
| I1 | ✗ | ✗ | ✓ (disj. bug) | ✗ |
| I2 | ✗ | ✗ | ✓ (disj. bug) | ✗ |
| I3 | ✗ | ✗ | ✓ (disj. bug) | ✗ |
The world-ordering column illustrates the "disjunction problem": Halpern's l-lifting validates patterns (I1–I3) that are invalid under measure semantics, showing that world-ordering semantics is strictly stronger than intended. V11 and V13 are invalid for l-lifting (Fact 1 in the paper).
"Probably A" — A is strictly more likely than its complement.
Equations
- Core.Scale.probably ge A = Core.Scale.strict ge A Aᶜ
Instances For
V1: △A → ¬△Aᶜ (probably A implies not probably not-A).
Equations
- Core.Scale.patternV1 ge = ∀ (A : Set W), Core.Scale.probably ge A → ¬Core.Scale.probably ge Aᶜ
Instances For
V2: △(A ∩ B) → △A ∧ △B (probably conjunction implies probably each conjunct).
Equations
- Core.Scale.patternV2 ge = ∀ (A B : Set W), Core.Scale.probably ge (A ∩ B) → Core.Scale.probably ge A ∧ Core.Scale.probably ge B
Instances For
V3: △A → △(A ∪ B) (probably A implies probably any disjunction containing A).
Equations
- Core.Scale.patternV3 ge = ∀ (A B : Set W), Core.Scale.probably ge A → Core.Scale.probably ge (A ∪ B)
Instances For
V6: □A → △A (necessarily A implies probably A). □A is ¬◇¬A = ge ∅ Aᶜ in the set-theoretic framework (@cite{holliday-icard-2013}, Figure 1).
Equations
- Core.Scale.patternV6 ge = ∀ (A : Set W), ge ∅ Aᶜ → Core.Scale.probably ge A
Instances For
V7: △A → ◇A (probably implies possibly).
Equations
- Core.Scale.patternV7 ge = ∀ (A : Set W), Core.Scale.probably ge A → Core.Scale.possibly ge A
Instances For
V11: B ≿ A → △A → △B (if B is at least as likely as a probable set, then B is probable). Uses the comparative ≿, not set inclusion ⊆. Invalid for l-lifting (Fact 1 in @cite{holliday-icard-2013}).
Equations
- Core.Scale.patternV11 ge = ∀ (A B : Set W), ge B A → Core.Scale.probably ge A → Core.Scale.probably ge B
Instances For
V12: B ≿ A → A ≿ Aᶜ → B ≿ Bᶜ (if B is at least as likely as a set that is more likely than not, then B is more likely than not). Uses the comparative ≿, not set inclusion ⊆.
Equations
- Core.Scale.patternV12 ge = ∀ (A B : Set W), ge B A → ge A Aᶜ → ge B Bᶜ
Instances For
V13: (A \ B) ≻ ∅ → (A ∪ B) ≻ B (positive excess implies strict increase).
Equations
- Core.Scale.patternV13 ge = ∀ (A B : Set W), Core.Scale.strict ge (A \ B) ∅ → Core.Scale.strict ge (A ∪ B) B
Instances For
I3: △A → A ≿ B (probably implies universally maximal — INVALID for measures).
Equations
- Core.Scale.patternI3 ge = ∀ (A B : Set W), Core.Scale.probably ge A → ge A B
Instances For
I1 is invalid for measure semantics: with uniform measure on Fin 3, {0} ≿ {1} and {0} ≿ {2} but ¬({0} ≿ {1,2}).
I2 is invalid for measure semantics: with uniform measure on Fin 3, {0,1} ≿ {0,1}ᶜ but ¬({0,1} ≿ univ).
I3 is invalid for measure semantics: with uniform measure on Fin 3, probably({0,1}) but ¬({0,1} ≿ univ).
I1 is invalid for FA: the measure-induced FA system on Fin 3 is a
counterexample (every finitely additive measure induces an FA system
via toSystemFA).
I2 is invalid for FA.
I3 is invalid for FA.
Recall: halpernLift ge_w A B := ∀ b, b ∈ B → ∃ a, a ∈ A ∧ ge_w a b.
So halpernLift ge_w A B means every element of B is dominated by some
element of A.
V11 is invalid for world-ordering semantics (Fact 1 in @cite{holliday-icard-2013}). Counterexample: W = Fin 2, ge_w total. A = W (probably, since W ≿ ∅ and ¬(∅ ≿ W)). B = {0} (B ≿ A since ge_w is total, but Bᶜ = {1} ≿ B since ge_w is total — not strictly).
V12 is valid for world-ordering semantics with a preorder (Fact 1 in @cite{holliday-icard-2013}). Requires transitivity for the case where y ∈ Bᶜ ∩ Aᶜ: chain through A via ge A Aᶜ, then through B via ge B A.
V13 is invalid for world-ordering semantics. Counterexample: W = Fin 2, ge_w = total (everything related). A = {0}, B = {1}. Then (A \ B) ≻ ∅ holds but (A ∪ B) ≻ B fails because ge B (A ∪ B).
I1 is valid for world-ordering semantics: the "disjunction problem".
I2 is valid for world-ordering semantics.
I3 is valid for world-ordering semantics.
The m-lifting validates all 13 validity patterns V1–V13 and invalidates I1–I3 (Fact 5 in @cite{holliday-icard-2013}). This avoids the "disjunction problem" that plagues the l-lifting.
V1, V3–V7 follow from the l-lifting proofs (since m-lifting implies
l-lifting). V2, V11–V13 use the injection structure directly;
V11–V12 rely on complement reversal (`mLift_complement_reversal`).
Every m-lift entails an l-lift: if there is an injection from B to A with each image dominating its preimage, then in particular every element of B is dominated by some element of A.
V2 is valid for the m-lifting: △(A ∩ B) → △A ∧ △B.
Proof: restrict the injection f : (A∩B)ᶜ ↪ A∩B to Aᶜ ⊆ (A∩B)ᶜ to get the ge half. For the strict half, any reverse injection g : A ↪ Aᶜ restricts to A∩B ↪ (A∩B)ᶜ (since Aᶜ ⊆ (A∩B)ᶜ), contradicting the hypothesis ¬mLift (A∩B)ᶜ (A∩B). Symmetric for B.
V12 is valid for the m-lifting on finite posets (Fact 5 in @cite{holliday-icard-2013}; proof via @cite{harrison-trainor-holliday-icard-2018}, Lemma 3.7). The proof decomposes into complement reversal (mLift ge_w B A → mLift ge_w Aᶜ Bᶜ) and two applications of mLift transitivity: B ≿ A ≿ Aᶜ ≿ Bᶜ.
V11 is valid for the m-lifting on finite posets (Fact 5 in @cite{holliday-icard-2013}). The ge half follows from V12; the strict half uses complement reversal + transitivity to derive a contradiction with the "probably A" hypothesis.
V13 is valid for the m-lifting on finite posets (Fact 5 in @cite{holliday-icard-2013}). The ge half uses id on B (reflexivity); the strict half uses pigeonhole (|A∪B| > |B| since A\B nonempty, finiteness).
I1 is invalid for the m-lifting (Fact 5 in @cite{holliday-icard-2013}). Counterexample: W = Fin 2, ge_w total. A = {0}, B = {0}, C = {1}. mLift A B and mLift A C both hold (singleton ↪ singleton), but ¬mLift A (B ∪ C) since |A| = 1 < 2 = |B ∪ C| (no injection).
I2 is invalid for the m-lifting (Fact 5 in @cite{holliday-icard-2013}). Counterexample: W = Fin 3, ge_w total. A = {0,1}, B = univ. mLift A Aᶜ holds (|Aᶜ| = 1 ≤ 2 = |A|), but ¬mLift A univ since |A| = 2 < 3 = |univ|.
I3 is invalid for the m-lifting (Fact 5 in @cite{holliday-icard-2013}). Same counterexample as I2: W = Fin 3, ge_w total, A = {0,1}, B = univ. A ≿ Aᶜ (injection {2} → {0,1}) and ¬(Aᶜ ≿ A) (no injection {0,1} → {2}), so probably A. But ¬(A ≿ univ) by cardinality.
The m-lifting is NOT total, even for total preorders on worlds. Counterexample: W = Fin 4, ge_w = (· ≥ ·), A = {3, 0}, B = {2, 1}. Neither A ≿ⁱ B (only 3 dominates 2, leaving nothing for 1) nor B ≿ⁱ A (nothing in B dominates 3).
The m-lifting of a reflexive, transitive world ordering on finite W is a GFC preorder (@cite{harrison-trainor-holliday-icard-2018}, Theorem 3.2).
This is the key structural result connecting world-ordering semantics to the axiomatic hierarchy: the injection extension ≿ⁱ (= mLift) satisfies all three GFC axiom groups — preorder (G), monotonicity (F), and complement reversal (C).
Equations
- Core.Scale.mLift_toGFCPreorder ge_w hRefl hTrans = { ge := Core.Scale.mLift ge_w, refl := ⋯, trans := ⋯, mono := ⋯, complRev := ⋯ }