OAI/GroupTheory/PolycyclicRecognition/Algebra/UnipotentGroupNilpotent.lean

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11 declarations, 0 contain sorry, 0 declared as axioms

Nilpotence from a faithful upper-unipotent representation

The entry filtration records the diagonal on which a matrix can first be nonzero. Commutators advance this filtration. The finite matrix size then bounds the lower central series of the represented group.

  1. def OAI.PolycyclicRecognition.MatrixDepth line 21

    Source documentation

    Vanishing on all diagonals strictly below the k-th upper diagonal.

    def MatrixDepth (k : ℕ) (X : Matrix (Fin n) (Fin n) R) : Prop :=
    …
  2. theorem OAI.PolycyclicRecognition.MatrixDepth.zero line 26
  3. theorem OAI.PolycyclicRecognition.MatrixDepth.mono line 30
  4. theorem OAI.PolycyclicRecognition.MatrixDepth.add line 35
  5. theorem OAI.PolycyclicRecognition.MatrixDepth.neg line 40
  6. theorem OAI.PolycyclicRecognition.MatrixDepth.sub line 45
  7. theorem OAI.PolycyclicRecognition.MatrixDepth.mul line 49
  8. theorem OAI.PolycyclicRecognition.MatrixDepth.one line 60
  9. theorem OAI.PolycyclicRecognition.MatrixDepth.eq_zero line 65
  10. theorem OAI.PolycyclicRecognition.MatrixDepth.of_strictUpper line 70
  11. theorem OAI.PolycyclicRecognition.nilpotent_of_faithful_strictUpper_representation line 81

    Source documentation

    A common finite upper-unipotent realization bounds the group lower central series, without any finiteness assumption on the represented group.

    theorem nilpotent_of_faithful_strictUpper_representation
        (ρ : H →* (Matrix (Fin n) (Fin n) R)ˣ) (hinj : Function.Injective ρ)
        (hu : ∀ h, StrictUpper ((ρ h : Matrix (Fin n) (Fin n) R) - 1)) :
        Group.IsNilpotent H := by
    …

    Mentions: OAI.PolycyclicRecognition.StrictUpper