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Ordinal.principal_mul_iff_le_two_or_omega0_opow_opow

Deprecated since 2026-03-17Use Ordinal.isPrincipal_mul_iff_le_two_or_omega0_opow_opow instead.

∀ {o : Ordinal.{u}},
  Ordinal.IsPrincipal (fun x1 x2 => x1 * x2) o ↔ o ≤ 2 ∨ o ∈ Set.range fun x => Ordinal.omega0 ^ Ordinal.omega0 ^ x

Alias of Ordinal.isPrincipal_mul_iff_le_two_or_omega0_opow_opow. The main characterization theorem for multiplicative principal ordinals.

Defined in
Mathlib.SetTheory.Ordinal.Principal
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0 results in Mathlib
Foundations
Depth 101 from the axioms · uses propext, Classical.choice, Quot.sound

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