Use this tag for questions related to simple functions
Simple functions are finite sums involving the characteristic functions of a set. They are real-valued functions on subsets of $\mathbb{R}$.
Simple functions are closed under addition and multiplication.
They are the foundation of Lebesgue integration (because the integration of simple functions is easy to define). A function $f$ can be approximated by simple functions allowing the calculation of the Lebesgue integral.
