surjection

As a noun surjection is

(set theory) a function of "many-to-one" mapping relationship; more formally, f'': ''x'' → ''y'' is a surjection if and only if, for every ''y'' in the codomain ''y'', there is at least one ''x'' in the domain ''x'' with ''f''(''x'') = ''y .

As nouns the difference between surjection and subjection

is that surjection is (set theory) a function of "many-to-one" mapping relationship; more formally, f'': ''x'' → ''y'' is a surjection if and only if, for every ''y'' in the codomain ''y'', there is at least one ''x'' in the domain ''x'' with ''f''(''x'') = ''y while subjection is the act of bringing something under the control of something else.

As nouns the difference between taxonomy and surjection

is that taxonomy is the science or the technique used to make a classification while surjection is (set theory) a function of "many-to-one" mapping relationship; more formally, f'': ''x'' → ''y'' is a surjection if and only if, for every ''y'' in the codomain ''y'', there is at least one ''x'' in the domain ''x'' with ''f''(''x'') = ''y .

As a noun surjection

is a function of "many-to-one" mapping relationship; more formally, f: X → Y is a surjection if and only if, for every y in the codomain Y, there is at least one x in the domain X with f(x) = y.

As an adjective subcountable is

being the target of a partial surjection from the natural numbers, such that the set of numbers used to count is no larger than the set being counted.