OAI/Topology/CoarseAssembly/TranscendentalUnit.lean

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A transcendental principal p-adic unit

The holonomy construction chooses a transcendental element of 1 + 2ℤ₂. The existence proof below works for every prime: algebraic elements form a countable set, and the Baire theorem makes its complement dense in the complete, perfect p-adic field.

  1. theorem OAI.CoarseAssembly.dense_padic_transcendental line 25

    Source documentation

    Transcendental elements over the integers are dense in the p-adic field.

    theorem dense_padic_transcendental : Dense {x : ℚ_[p] | Transcendental ℤ x} := by
    …
  2. theorem OAI.CoarseAssembly.exists_transcendental_principal_unit line 38

    Source documentation

    The exact principal-unit choice needed for diagonal holonomy exists. The specialization p = 2 lies in 1 + 2ℤ₂.

    theorem exists_transcendental_principal_unit :
        ∃ t : ℤ_[p]ˣ, Transcendental ℤ (t : ℤ_[p]) ∧
          ∃ a : ℤ_[p], (t : ℤ_[p]) = 1 + (p : ℤ_[p]) * a := by
    …