What exactly is your difficulty? Do you know what "injection" and "surjection" mean? It should be very easy to do part (a) or part (c). Parts (b) and (d) are a little harder. Can you use the fact that , , and are all "countable" sets?
I need help! can someone help me with this?
Prove or disprove the following statements:
(a) There exists an injection fromN to N^2.
(b) There exists a surjection from N to N^2.
(c) There exists an injection from N to N^3.
(d) There exists a surjection from N to N^3.
where N is the set of natural numbers.
Have you seen this before?