; QED &gt;=======================o

This is not only a logically equivalent DNF,
but exactly the same DNF expression that we
obtained before, so we have established the
given equation &quot;(p (q))(p (r)) = (p (q r))&quot;.

Incidentally, one may wish to note that this DNF
expression quickly folds into the following form:

o-----------------------------------------------------------o
|                                                           |
|                     pqr o-------o---o p                   |
|