The graph of a function f : D → R {\displaystyle f\colon D\to R} is the set of ordered pairs ( x , y ) {\displaystyle (x,y)} such that x ∈ D , y ∈ R {\displaystyle x\in D,y\in R} and y = f ( x ) {\displaystyle y=f(x)} .
Symbolically:
i.e. graph ( f ) {\displaystyle \text{graph}(f)} is a subset of D × R {\displaystyle D\times R}