Re: Types of functions and relations

James Buddenhagen wrote: 
You may possibly have a misunderstanding here.  A common terminology is:

   A is the 'domain' of f
   B is the 'codomain' of f  (some say 'target' instead of 'codomain')

	That is my understanding too.



The function f maps elements of A to elements of B (not to pairs in AxB
as you state).  If 'a' is in A and f(a)=b, then 'b' is called the image
of 'a' under f, and 'a' is a pre-image of b.  The set of all images of
elements of A under f is a subset of B (possibly all of B) called the
'range of f'.

Understood. What I meant was that a function can be seen as a set whose elements are certain pairs from AxB. Not all of them, just some. When we say that f(a) = b, it means that the pair (a,b) is an element of F<=AxB. I did not know what to call such a set.



The subset F you describe above of all pairs (a,b) such that 'a' is
in A, 'b' is in B and f(a)=b is commonly called the 'graph' of f.

	Okay. I will call it the graph until further notice.


	Thanks, Adam.
.