Question 454883
<pre><font face = "consolas" color = "indigo" size = 4><b>
&#8764;(p &#8594; q), p &#8743; &#8764;q


| p | q | ~q | p &#8594; q | &#8764;(p &#8594; q) | p &#8743; &#8764;q |
———————————————————————————————————————————
| T | T |  F |   T   |     F    |    F    |
| T | F |  T |   F   |     T    |    T    |
| F | T |  F |   T   |     F    |    F    |
| F | F |  T |   T   |     F    |    F    |

The last two columns are the same FTFF, so they
are equivalent and we can now write:

      &#8764;(p &#8594; q) &#8660; p &#8743; &#8764;q

Edwin</pre>