arity

In logic, mathematics, and computer science, arity () is the number of arguments or operands taken by a function, operation or relation. In mathematics, arity may also be called rank, but this word can have many other meanings. In logic and philosophy, arity may also be called adicity and degree. In linguistics, it is usually named valency.

== Examples == In general, functions or operators with a given arity follow the naming conventions of n-based numeral systems, such as binary and hexadecimal. A Latin prefix is combined with the -ary suffix. For example: A nullary function takes no arguments. Example: f()=2 A unary function takes one argument. Example: f(x)=2x A binary function takes two arguments. Example: f(x,y)=2xy A ternary function takes three arguments. Example: f(x,y,z)=2xyz An n-ary function takes n arguments. Example: f(x_1, x_2, \ldots, x_n)=2\prod_{i=1}^n x_i