Question 1195750
<pre>

1. Z v ~Z                  tautology
2. Z v (~Z v Q)            1, addition
3. Z v (Z ⊃ Q)             2, material implication
4. [Z v (Z ⊃ Q)] v M       3, addition
5.  ~~{[Z v (Z ⊃ Q)] v M}  4, double negation

But that does not use indirect proof

1.                         | ~~~{[Z v (Z ⊃ Q)] v M}I    AIP
2.                         |


Edwin</pre>