English
There exists a measurable equivalence between realMixedSpace K and polarSpace K.
Русский
Существует измеримое эквивалентное отображение между realMixedSpace K и polarSpace K.
LaTeX
$$$\\exists\\, \\text{measurableEquivRealMixedSpacePolarSpace}(K) : \\text{realMixedSpace}(K) \\simeq_m \\text{polarSpace}(K)$$$
Lean4
/-- The measurable equivalence between the `realMixedSpace` and the `polarSpace`. It is actually an
homeomorphism, see `homeoRealMixedSpacePolarSpace`, but defining it in this way makes it easier
to prove that it is volume preserving, see `volume_preserving_homeoRealMixedSpacePolarSpace`.
-/
def measurableEquivRealMixedSpacePolarSpace : realMixedSpace K ≃ᵐ polarSpace K :=
MeasurableEquiv.trans (prodCongr (refl _) (arrowProdEquivProdArrow ℝ ℝ _)) <|
MeasurableEquiv.trans prodAssoc.symm <|
MeasurableEquiv.trans
(prodCongr
(prodCongr (refl _) (arrowCongr' (Equiv.subtypeEquivRight (fun _ ↦ not_isReal_iff_isComplex.symm)) (refl _)))
(refl _))
(prodCongr (piEquivPiSubtypeProd (fun _ ↦ ℝ) _).symm (refl _))