|Definition:|| relation f such that for any entity a there is exactly one entity b to which a is related by f|
NOTE 1 If a is related to b by the function f, then:
- f is said to be defined for a,
- a is an argument of the function f,
- b is a value of the function f and is usually denoted by f(a).
The argument a may be an ordered set of more elementary entities.
NOTE 2 If A is the set of all arguments of the function f and B is a set containing all the values, then:
- f is said to be a mapping of A into B,
- A is the domain of the function,
- B is the range or codomain of the function.
NOTE 3 The term "operation" is used in common language for elementary functions such as addition, subtraction, multiplication, division.