x_{1} is a function/single-valued mapping from domain x_{2} to range x_{3} defined by expression/rule x_{4}.

- bridi
- x
_{1}(du'u) is a predicate relationship with relation x_{2}among arguments (sequence/set) x_{3}. - mekso
- x
_{1}[quantifier/expression] is a mathematical expression interpreted under rules/convention x_{2}. - fatkajyfancu
- x
_{1}=fc_{1}is an inverse function from domain x_{2}=fc_{2}to range x_{3}=fc_{3}defined by original function x_{4}=f_{4} - nutko
- x
_{1}is the language/sublanguage that uses no apparent terbri/selbri distinction and is used by x_{2}to express ideas (not text) x_{3}. - pirxo
- x
_{1}is the language/sublanguage that uses no apparent recursion rules and is used by x_{2}to express ideas (not text) x_{3}. - funtiio
- x
_{1}(plural of ordered pairs) is an exhaustive set (possibly infinite) of inputs/outputs defining a unary function which yields result x_{3}when given input x_{2}; x_{1}(x_{2}) = x_{3} - integrale
- x
_{1}(number) is the integral (limit) of function x_{2}