Surjection/Examples/Arbitrary Example 2

Example of Surjection

Let $S$ and $T$ be sets such that:

\(\ds S\)

\(=\)

\(\ds \set {2, -2, 3}\)

\(\ds T\)

\(=\)

\(\ds \set {4, 9}\)

Let $f: S \to T$ be the mapping defined as:

$f: x \mapsto x^2$

Then $f$ is a surjection.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): surjection (onto, surjective function)
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): surjection (onto, surjective function)