Editing Indicator function (section)

==Notation and terminology==
The notation <math>\chi_A</math> is also used to denote the [[Characteristic function (convex analysis)|characteristic function]] in [[convex analysis]], which is defined as if using the [[Multiplicative inverse|reciprocal]] of the standard definition of the indicator function.

A related concept in [[statistics]] is that of a [[dummy variable (statistics)|dummy variable]]. (This must not be confused with "dummy variables" as that term is usually used in mathematics, also called a [[free variables and bound variables|bound variable]].)

The term "[[characteristic function (probability theory)|characteristic function]]" has an unrelated meaning in [[probability theory|classic probability theory]]. For this reason, [[List of probabilists|traditional probabilists]] use the term '''indicator function''' for the function defined here almost exclusively, while mathematicians in other fields are more likely to use the term ''characteristic function'' to describe the function that indicates membership in a set.

In [[fuzzy logic]] and [[Many-valued logic|modern many-valued logic]], predicates are the [[characteristic function (probability theory)|characteristic functions]] of a [[probability distribution]]. That is, the strict true/false valuation of the predicate is replaced by a quantity interpreted as the degree of truth.