6. A one-to-one correspondence from a set X to a set
Y is a function F: XY that
is both one-to-one and onto. That is, if you were to draw the arrow diagram for the
function, no two arrows from different elements of X would point to the same element in Y
and every element of Y would have an arrow pointing to it.
From the arrow diagram we can see that the function f is a one-to-one correspondence.