ProbabilityTheory.Kernel.hom_congr🔗

ProbabilityTheory.Kernel.hom_congr.{u_1, u_2, u_5} {X : Type u_1}
  {Y : Type u_2} [MeasurableSpace X] [MeasurableSpace Y]
  (SX SY : SFinKer) (ex : SFinKer.carrier SX ≃ᵐ X)
  (ey : SFinKer.carrier SY ≃ᵐ Y) (κ η : Kernel X Y) [IsSFiniteKernel κ]
  [IsSFiniteKernel η] : κ = η ↔ hom κ = hom η
ProbabilityTheory.Kernel.hom_congr.{u_1,
    u_2, u_5}
  {X : Type u_1} {Y : Type u_2}
  [MeasurableSpace X] [MeasurableSpace Y]
  (SX SY : SFinKer)
  (ex : SFinKer.carrier SX ≃ᵐ X)
  (ey : SFinKer.carrier SY ≃ᵐ Y)
  (κ η : Kernel X Y) [IsSFiniteKernel κ]
  [IsSFiniteKernel η] :
  κ = η ↔ hom κ = hom η

lemma hom_congr (SX SY : SFinKer) (ex : SX ≃ᵐ X) (ey : SY ≃ᵐ Y)
    (κ η : Kernel X Y) [IsSFiniteKernel κ] [IsSFiniteKernel η] :
    κ = η ↔ κ.hom (ex := ex) (ey := ey) = η.hom (ex := ex) (ey := ey)

by
  constructor
  · grind
  · intro h
    ext a s hs
    replace h := DFunLike.congr (x := ex.symm a) (congrArg SFinKer.Hom.hom h) rfl
    replace h := DFunLike.congr (x := ey.symm '' s) h rfl
    rw [hom_apply', hom_apply'] at h
    · simp only [apply_symm_apply] at h
      rwa [image_symm, image_preimage] at h
    · measurability
    · measurability

Meaning last changed in v4.34.0-rc2-1-g439785b (2026-08-23).

Self-contained, with its dependencies inlined and proofs replaced by sorry: download the raw file · open it in the Lean web editor.

Dependency graph

Audit surface: 1 project declarations, 20 external constants

✓ Proved: no sorry anywhere in its closure

This is the tool's own reading of one build's recorded axioms, and it is not robust against an author who wants it to pass. Checking meant to be relied on should go through Comparator, which replays the proof through the kernel from an export against an explicit list of permitted axioms.