If $f: A \rightarrow B$ is a bijection, then the function $f^{-1}: B \rightarrow A$ defined by
$$f^{-1}(b) = a \iff f(a) = b$$is called the inverse of $f$, denoted $f^{-1}$
If $f: A \rightarrow B$ is a bijection, then the function $f^{-1}: B \rightarrow A$ defined by
$$f^{-1}(b) = a \iff f(a) = b$$is called the inverse of $f$, denoted $f^{-1}$