===== Negative part of a function =====
==== Set ====
| @#55CCEE: context     | @#55CCEE: $f:X\to \overline{\mathbb R}$ |

| @#FFBB00: definiendum | @#FFBB00: $f^-:X\to \overline{\mathbb R}$ |
| @#FFBB00: definiendum | @#FFBB00: $ f^-(x) := \mathrm{max}(-f(x),0)$ |

==== Discussion ====
Notice that $f^-(x)\ge 0$.
==== Parents ====
=== Context ===
[[Maximum function]], [[Extended real number line]]