English
The positive part of mk f hf equals mk of max(f,0) with an appropriate measurability proof.
Русский
Положительная часть функции mk f hf равна mk максимума max(f,0) с корректной доказуемостью измеримости.
LaTeX
$$$\\operatorname{posPart}(\\mathrm{mk} f hf) = \\mathrm{mk}\\bigl(\\lambda x. \\max(f(x),0)\\bigr)\\bigl( (\\mathrm{continuous\_id}.\\mathrm{max}\\mathrm{continuous\_const}).\\mathrm{comp\_aestronglyMeasurable}\\ hf \\bigr)$$$
Lean4
theorem coeFn_star [Star R] [ContinuousStar R] (f : α →ₘ[μ] R) : ↑(star f) =ᵐ[μ] (star f : α → R) :=
coeFn_comp _ (continuous_star) f