The image of a measurable set under a map that is continuous and injective on a closed subset of a compact space (into a Hausdorff space) is measurable.
ProvedTypeDensity.image_measurable_of_continuousOn_injOn_compacttype-density
The image of a measurable set under a map that is continuous and injective on a closed subset of a compact space (into a Hausdorff space) is measurable.
Preamble
import Definitions.Def_TypeDensity_Basic import Definitions.Def_TypeDensity_Formula_LawAlgebra import Mathlib.FieldTheory.RatFunc.Basic import Mathlib.MeasureTheory.Measure.Haar.Unique import Mathlib.NumberTheory.ArithmeticFunction.Moebius import Mathlib.NumberTheory.Padics.PadicIntegers import Mathlib.RingTheory.IntegralClosure.IntegralRestrict import Mathlib.RingTheory.MvPowerSeries.Basic import Mathlib.RingTheory.RamificationInertia.Basic import Mathlib.Topology.Algebra.Nonarchimedean.AdicTopology import Mathlib.FieldTheory.Finite.GaloisField import Mathlib.RingTheory.AdicCompletion.Algebra import Mathlib.RingTheory.RegularLocalRing.Defs set_option autoImplicit false open TypeDensity open scoped BigOperators ENNReal
Formal statement
theorem TypeDensity.image_measurable_of_continuousOn_injOn_compact (X Y : Type) [TopologicalSpace X]
[CompactSpace X] [MeasurableSpace X] [BorelSpace X] [TopologicalSpace Y] [T2Space Y]
[MeasurableSpace Y] [BorelSpace Y] (f : X → Y) (C : Set X) (hC : IsClosed C)
(hf : ContinuousOn f C) (hinj : Set.InjOn f C) (U : Set X) (hU : MeasurableSet U) :
MeasurableSet (f '' (U ∩ C)) := by sorrySource
TypeDensity/Formula/LawAlgebra.lean#L864-L875