English
If two locally finite measures μ,ν on R agree on all open intervals Ioo with rational endpoints, then μ = ν.
Русский
Если две locally-finite меры μ, ν на ℝ согласованы на все открытые интервалы Ioo с рациональными границами, то μ = ν.
LaTeX
$$$\\\\forall μ ν : \\\\mathrm{Measure}(\\\\mathbb{R}), [\\\\operatorname{IsLocallyFiniteMeasure} μ], [\\\\operatorname{IsLocallyFiniteMeasure} ν], (\\\\forall a,b \\\\in \\\\mathbb{Q}, μ(Ioo(a,b)) = ν(Ioo(a,b))) \\\\Rightarrow μ = ν$$$
Lean4
@[measurability, fun_prop]
theorem measurable_real_toNNReal : Measurable Real.toNNReal :=
continuous_real_toNNReal.measurable