English
A variant of lintegral_sub_le' for ENNReal with h f measurable, giving le inequalities between subtractions.
Русский
Вариант lintegral_sub_le' для ENNReal при измеримости f, дающий неравенства между вычитаниями.
LaTeX
$$$(f,g : α → ENNReal) (hf : AEMeasurable f μ) : ∫⁻ x, g(x) ∂μ - ∫⁻ x, f(x) ∂μ ≤ ∫⁻ x, g(x) ∂μ - ∫⁻ x, f(x) ∂μ$$$
Lean4
theorem lintegral_sub_le' (f g : α → ℝ≥0∞) (hf : AEMeasurable f μ) : ∫⁻ x, g x ∂μ - ∫⁻ x, f x ∂μ ≤ ∫⁻ x, g x - f x ∂μ :=
by
rw [tsub_le_iff_right]
by_cases hfi : ∫⁻ x, f x ∂μ = ∞
· rw [hfi, add_top]
exact le_top
· rw [← lintegral_add_right' _ hf]
gcongr
exact le_tsub_add