Surjection

A surjection is a function f:X→Y such that for each y∈Y there is at least one x∈X such that f(x)=y.

Example

The function f(x)=x is a surjection.

References

A. Menzes, P. van Oorschot, and S. Vanstone, Handbook of Applied Cryptography. CRC Press, 1996.