Suppose { f n } {\displaystyle \{f_{n}\}} is a sequence of non-negative measurable functions, f n : X → [ 0 , + ∞ ] {\displaystyle f_{n}:X\to [0,+\infty ]} . Then: ∫ lim inf n → + ∞ f n ≤ lim inf n → + ∞ ∫ f n {\displaystyle \int \liminf _{n\rightarrow +\infty }f_{n}\leq \liminf _{n\rightarrow +\infty }\int f_{n}} .
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