ThmDex – An index of mathematical definitions, results, and conjectures.
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Definition D1747
Unsigned basic integral
Formulation 0
Let $M = (X, \mathcal{F}, \mu)$ be a D1158: Measure space such that
(i) $\text{MS} = \text{MS}(X \to [0, \infty])$ is the D2958: Set of measurable simple functions on $M$
(ii) $f : X \to [0, \infty]$ is a D313: Measurable function on $M$
The unsigned basic integral of $f$ with respect to $M$ is the D5237: Unsigned basic number \begin{equation} \int_X f \, d \mu : = \sup_{\phi \in \text{MS} : 0 \leq \phi \leq f} \int_X \phi \, d \mu \end{equation}
Formulation 1
Let $M = (X, \mathcal{F}, \mu)$ be a D1158: Measure space such that
(i) $\text{MS} = \text{MS}(X \to [0, \infty])$ is the D2958: Set of measurable simple functions on $M$
(ii) $f : X \to [0, \infty]$ is a D313: Measurable function on $M$
The unsigned basic integral of $f$ with respect to $M$ is the D5237: Unsigned basic number \begin{equation} \int_X f \, d \mu : = \sup \left\{ \int_X \phi \, d \mu \mid \phi \in \text{MS} \text{ such that } 0 \leq \phi \leq f \right\} \end{equation}
Children
D5103: Unsigned basic expectation
Results
R1233: Finite additivity of unsigned basic integral
R1236: Markov's inequality
R1232: Tonelli's theorem for sums and integrals
R2089: Unsigned basic expectation is compatible with probability measure
R5300: Unsigned basic integral over an empty set equals zero