English
For any s and any i with ω1 ≤ i, the i-th stage of the transfinite generation equals the ω1-th stage: generateMeasurableRec(s,i) = generateMeasurableRec(s, ω1).
Русский
Для любого s и любого i с ω1 ≤ i тождественна стадия i порождения: generateMeasurableRec(s,i) = generateMeasurableRec(s, ω1).
LaTeX
$$$\\text{generateMeasurableRec}(s,i) = \\text{generateMeasurableRec}(s, \\omega_1) \\quad\\text{whenever } \\omega_1 \\le i$$$
Lean4
/-- `generateMeasurableRec` is constant for ordinals `≥ ω₁`. -/
theorem generateMeasurableRec_of_omega1_le (s : Set (Set α)) {i : Ordinal.{v}} (hi : ω₁ ≤ i) :
generateMeasurableRec s i = generateMeasurableRec s (ω₁ : Ordinal.{v}) :=
by
apply (generateMeasurableRec_mono s hi).antisymm'
rw [← generateMeasurable_eq_rec]
exact generateMeasurableRec_subset s i