English
The map lpMeasSubgroupToLpTrim is a left inverse of lpTrimToLpMeasSubgroup: composing lpMeasSubgroupToLpTrim after lpTrimToLpMeasSubgroup yields the original element.
Русский
Отображение lpMeasSubgroupToLpTrim является левым обратным к lpTrimToLpMeasSubgroup: композиция даёт исходный элемент.
LaTeX
$$$\text{LeftInverse}\bigl( lpTrimToLpMeasSubgroup\ F\ p\ μ\ hm\bigr)(\,lpMeasSubgroupToLpTrim\ F\ p\ μ\ hm\, f) = f$$$
Lean4
/-- `lpTrimToLpMeasSubgroup` is a left inverse of `lpMeasSubgroupToLpTrim`. -/
theorem lpMeasSubgroupToLpTrim_left_inv (hm : m ≤ m0) :
Function.LeftInverse (lpTrimToLpMeasSubgroup F p μ hm) (lpMeasSubgroupToLpTrim F p μ hm) :=
by
intro f
ext1
ext1
exact (lpTrimToLpMeasSubgroup_ae_eq hm _).trans (lpMeasSubgroupToLpTrim_ae_eq hm _)