Source-pinned research

Research proof index

Search theorem names, mathematical ideas, modules, topics, projects, and role-labelled researchers. Open a result for its complete indexed Lean declaration and source record.

This index contains 31 research declarations. Search 10,000 more complete Mathlib declarations.

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Project-declaredLean 4.32.1

Computable Pred iff decoded pred

ComputablePred.iff_decoded_pred

Plain-language statement

Computability of a predicate on a Primcodable type is equivalent to the computability of the corresponding predicate on obtained by decoding.

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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Project-declaredLean 4.32.1

Bv quote fixitr

LO.FirstOrder.Arithmetic.Bootstrapping.bv_quote_fixitr

Plain-language statement

bv-pin bridge (over ℕ): bv ⌜fixitr 0 (fvSup χ) ▹ χ⌝ = fvSup χ. - is immediate from quote_univCl_eq + bv_qqAlls (closing fvSup quantifiers reaches a sentence, whose bv is 0). - is by level-factoring: were the body an IsSemiformula j for some j < fvSup, IsSemiformula.sound + castLE-invariance would re-express χ as `γ ⇜ ![...

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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Project-declaredLean 4.32.1

Conj

LO.FirstOrder.Arithmetic.Bootstrapping.Derivable.conj

Plain-language statement

Crucial inducion for formalized Σ1\Sigma_1-completeness.

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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Project-declaredLean 4.32.1

Fvar Vec val eq

LO.FirstOrder.Arithmetic.Bootstrapping.fvarVec_val_eq

Plain-language statement

fvarVec is the code of the typed substitution vector fun i ↦ ^&i (over a standard length).

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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Project-declaredLean 4.32.1

Is Sigma1 of all

LO.FirstOrder.Arithmetic.Bootstrapping.IsSigma1.of_all

Plain-language statement

Inversion of the bounded- clause: a ^∀-headed 𝚺₁ code is a qqBall.

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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Project-declaredLean 4.32.1

Le term BShift

LO.FirstOrder.Arithmetic.Bootstrapping.le_termBShift

Plain-language statement

termBShift only grows codes: t ≤ termBShift t for well-formed terms. The ^#z → ^#(z+1) bvar shift grows, ^&x is fixed, and functions recurse componentwise. Bounds the ∃ t guard in the bounded- clause.

formal logicmetatheoryproof theory

Source project: Foundation

Person-level attribution pending.

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