Question: a) Define what it means for a function from the set of positive integers to the set of positive integers to be one-to-one.
b) Define what it means for a function from the set of positive integers to the set of positive integers to be onto.
c) Give an example of a function from the set of positive integers to the set of positive integers that is both one-to-one and onto.
d) Give an example of a function from the set of positive integers to the set of positive integers that is one-to-one but not onto.
e) Give an example of a function from the set of positive integers to the set of positive integers that is not one-to-one but is onto.
f) Give an example of a function from the set of positive integers to the set of positive integers that is neither one-to-one nor onto.