Definition 22.3.2 (Positive and Negative Parts).label Let $X$ be a set and $f: X \to \real$ be a function, then
\[f^{+} = f \vee 0 \quad f^{-} = -(f \wedge 0)\]
are the positive and negative parts of $f$, and $f = f^{+} - f^{-}$.
Definition 22.3.2 (Positive and Negative Parts).label Let $X$ be a set and $f: X \to \real$ be a function, then
are the positive and negative parts of $f$, and $f = f^{+} - f^{-}$.