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  "natural_language_statement": "Let x be self-adjoint in a unital complex C*-algebra A. There exists a maximal abelian unital star subalgebra D of A containing x.",
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      "text": "The source turns self-adjointness into IsStarNormal x and applies exists_maximalAbelian_containing. Normality is an intermediate premise, not the theorem's conclusion."
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    "text": "theorem exists_maximalAbelian_containing_isSelfAdjoint\n    (x : A) (hx : IsSelfAdjoint x) :\n    ∃ D : StarSubalgebra ℂ A, IsMaximalAbelian D ∧ x ∈ D"
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