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When we write |X|=m, we mean that X is a finite set that contains
exactly m elements; i.e., the cardinality of X is m.
- If |X|=m and |Y|=n, how many relations between X and Y
are there?
- If |X|=m and |Y|=n, how many functions are there?
- Suppose |X|=m, |Y|=n, and is a
function.
Try to fill in the following table by giving a formula for the number
of functions in each case:
- How many ways are there of removing a regular tetrahedron from
the table and replacing it in the same position, but not necessarily
with the same sides facing the same directions as before?
- How many ways are there of removing a cube from
the table and replacing it in the same position, but not necessarily
with the same sides facing the same directions as before?
Carl Lee
Wed Sep 30 08:36:10 EDT 1998