this week we started to look at the things we can do with the ordered pairs (<a,b>) that we introduced last time.

we saw that we can put them in sets, and that that gives us a way to talk about relations that hold between members of two sets – one from which the first members of the ordered pairs are drawn (we called that the domain), and one from which the second members are drawn (the range). A relation from the domain A to the range B is then a set of ordered pairs which have some member of A as their first and some member of B as their second element.

we identified functions as a particular class of relations, namely those relations where every member of the domain is paired with exactly one member of the range. (note that this allows for several members of the domain to be paired up with the same member of the range.)

here is a copy of the exercises we did this week, you’re encouraged to turn in some of your results to get comments back.