ADVICE on choosing a rule appropriate to the operator '~' (NOT)
| suggestions: | ||
| If ~ | is the Main Operator in a PREMISE, | MT DS |
| the MO in the GOAL or CONCLUSION, | MT | |
| to be LEFT AS IS while others change, | DN | |
| to be REPLACED with another operator, | DM TAUT |
Note: if the conclusion or goal proposition is IDENTICAL to a portion of a premise, then chose the rule according to that PREMISE'S main operator.
~( ) almost always leads to a DeMorgan's rule.