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Project-declaredLean 4.21.0-rc3 · mathlib@5b77ef3c

Categorise permutative Extension of one One

Rel.categorise_permutativeExtension_of_oneOne

Plain-language statement

TODO: Strengthen statement in blueprint version.

Exact Lean statement

theorem categorise_permutativeExtension_of_oneOne
    {r : Rel α α} (R : OrbitRestriction (r.dom ∪ r.codom) β) (hr : r.OneOne)
    {a₁ a₂ : α} (h : r.permutativeExtension R a₁ a₂) :
    r a₁ a₂ ∨ (a₁ ∉ r.dom ∧ a₂ ∉ r.codom ∧ R.categorise a₂ = R.catPerm (R.categorise a₁))

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem categorise_permutativeExtension_of_oneOne    {r : Rel α α} (R : OrbitRestriction (r.domr.codom) β) (hr : r.OneOne)    {a₁ a₂ : α} (h : r.permutativeExtension R a₁ a₂) :    r a₁ a₂  (a₁  r.dom  a₂  r.codom  R.categorise a₂ = R.catPerm (R.categorise a₁)) := by  by_cases ha₁ : a₁  r.dom  · obtain b₁, h₁ := ha₁    cases (r.permutativeExtension_permutative R hr).coinjective h (Or.inl h₁)    exact Or.inl h₁  by_cases ha₂ : a₂  r.codom  · obtain b₁, h₁ := ha₂    cases (r.permutativeExtension_permutative R hr).injective h (Or.inl h₁)    exact Or.inl h₁  · simp only [ha₁, ha₂, not_false_iff, true_and]    exact categorise_permutativeExtension R h
Project
Con(NF)
License
Apache-2.0
Commit
55b939a3acf9
Source
ConNF/Background/PermutativeExtension.lean:350-363

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Related declarations

Project-declaredLean 4.21.0-rc3

Smul near Litter of smul litter

ConNF.BaseAction.smul_nearLitter_of_smul_litter

Project documentation

The main lemma about how approximations interact with actions.

set theoryconsistencyfoundations

Source project: Con(NF)

Person-level attribution pending.

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Project-declaredLean 4.21.0-rc3

Smul interference

ConNF.BasePerm.smul_interference

Plain-language statement

Base permutations commute with the interference of near-litters.

set theoryconsistencyfoundations

Source project: Con(NF)

Person-level attribution pending.

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Project-declaredLean 4.21.0-rc3

Card t Set le

ConNF.card_tSet_le

Plain-language statement

Note that we cannot prove the reverse implication because all of our hypotheses at this stage are about permutations, not objects.

set theoryconsistencyfoundations

Source project: Con(NF)

Person-level attribution pending.

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