Inverse of Injection is One-to-One Relation
Theorem
Let $f$ be an injective mapping.
Then its inverse $f^{-1}$ is a one-to-one relation.
Proof
We are given that $f$ is an injective mapping.
Hence by definition $f$ is a one-to-one relation.
The result follows from from Inverse of One-to-One Relation is One-to-One.
$\blacksquare$
Sources
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): one-to-one function (one-to-one mapping, one-to-one map)