Question 928685
<pre>
1. h -> ~a
2. a
     // ~(h v ~a)

3. ~~a -> ~h     1,CP
4. a -> ~h       3,DN
5. ~h            4,2,MP
6. ~h & a        5,2,conjunction
7. ~h & ~~a      6,DN
8. ~(h v ~a)     7,DM

Edwin</pre>