ThmDex – An index of mathematical definitions, results, and conjectures.
Fatou's lemma for unsigned basic integral
Formulation 1
Let $M = (X, \mathcal{F}, \mu)$ be a D1158: Measure space such that
(i) $f_0, f_1, f_2, \cdots : X \to [0, \infty]$ are each an D5610: Unsigned basic Borel function on $M$
Then
(1) \begin{equation} \int_X \liminf_{n \to \infty} f_n \,d \mu \leq \liminf_{n \to \infty} \int_X f_n \,d \mu \end{equation}
(2) \begin{equation} \int_X \limsup_{n \to \infty} f_n \,d \mu \geq \limsup_{n \to \infty} \int_X f_n \,d \mu \end{equation}