f
| distributive law.
|
| h*k  =  (h &lt;k p1_D,B, p2_D,B&gt;)*,
|
| where h : A x B -&gt; C and k : D -&gt; A.
|
| Proof.  We show this as follows,
| omitting subscripts:
|
| h*k  =  (!e! &lt;h*k p1, p2&gt;)*
|
|      =  (!e! &lt;h*p1, p2&gt; &lt;k p1, p2&gt;)*
|
|      =  (h &lt;k p1, p2&gt;)*.
|
| Quite important is the following bijection,
| which holds in any cartesian closed category.
|
| Hom(A, B)  ~=~  Hom(1, B^A).
|
| Proof.  As in Section 1, with any f : A -&gt; B
| we associate #f : 1 -&gt; B^A, 