OAI/GroupTheory/PolycyclicRecognition/Algebra/NilpotentGenerators.lean

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4 declarations, 0 contain sorry, 0 declared as axioms

Lifting generators from the nilpotent abelianization

For the Cartan model, homogeneous lifts of a basis modulo the derived algebra generate the whole nilpotent ideal. The proof pushes the error down its actual lower central series; no generation hypothesis is substituted for this step.

  1. theorem OAI.PolycyclicRecognition.span_sup_lowerCentralSeries_one_of_lieSpan line 18

    Source documentation

    Lie generation implies linear spanning modulo brackets.

    theorem span_sup_lowerCentralSeries_one_of_lieSpan
        (S : Set L) (hS : LieSubalgebra.lieSpan ℝ L S = ⊤) :
        Submodule.span ℝ S ⊔ (LieModule.lowerCentralSeries ℝ L L 1).toSubmodule = ⊤ := by
    …
  2. theorem OAI.PolycyclicRecognition.lieSubalgebra_sup_lowerCentralSeries line 38
  3. theorem OAI.PolycyclicRecognition.lieSubalgebra_eq_top_of_sup_lowerCentralSeries_one line 77

    Source documentation

    Lifts spanning the abelianization generate a nilpotent Lie algebra.

    theorem lieSubalgebra_eq_top_of_sup_lowerCentralSeries_one
        [LieRing.IsNilpotent L] (U : LieSubalgebra ℝ L)
        (hU : U.toSubmodule ⊔ (LieModule.lowerCentralSeries ℝ L L 1).toSubmodule = ⊤) :
        U = ⊤ := by
    …
  4. theorem OAI.PolycyclicRecognition.exists_bracketWord_basis_of_abelianization line 87

    Source documentation

    The resulting generating family has a basis of evaluated bracket words.

    theorem exists_bracketWord_basis_of_abelianization
        [LieRing.IsNilpotent L] [FiniteDimensional ℝ L]
        {I : Type*} (X : I → L)
        (hX : Submodule.span ℝ (Set.range X) ⊔
          (LieModule.lowerCentralSeries ℝ L L 1).toSubmodule = ⊤) :
        ∃ b : Module.Basis (Fin (Module.finrank ℝ L)) ℝ L,
          ∀ k, ∃ w : FreeMagma I, evalBracketWord X w = b k := by
    …

    Mentions: OAI.PolycyclicRecognition.evalBracketWord