A
bijection is a
bijective function. A function
f:X->Y
is said to be bijective iff:
- given any y in Y there exists x in X such that
f(x)=y (f is surjective)
-
given any a,b in X if f(a)=f(b) then a=b
(f is injective)
An example of a bijection is the identity function 1X:X->X that maps each x in X to itself.