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*Definition*:
Let `f`: `A` -> `B`.
`f` is *injective* (*one-to-one*) if
it does not map different arguments to the same result:

f:A->^{injective}B: <=>f:A->B/\ (forallx_{0}inA,x_{1}inA:f(x_{0}) =f(x_{1}) =>x_{0}=x_{1}).

f:A->^{surjective}B: <=>f:A->B/\ (forallyinB:existsxinA:f(x) =y).

f:A->^{bijective}B: <=>f:A->^{injective}B/\f:A->^{surjective}B.

Author: Wolfgang Schreiner

Last Modification: December 7, 1999