# Mathematical Terms

#### Surjective function

For every in the co-domain , there is at least one in the domain so that . More than one value can map to any value.

#### Injective function

For every in the co-domain, there is at most one in the domain such that . Note that an injective function doesn't necessarily cover the whole co-domain. Noted by .

#### Bijective function

A function that is surjective as well as bijective, i.e. there is a one-to-one correspondence between the domain and the co-domain. Noted by . If then the bijective function is called a permutation.

Number

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