Double Negation/Double Negation Introduction/Proof Rule/Technical Note

Proof Rule
When invoking Double Negation Introduction in a tableau proof, use the DoubleNegIntro template:



or:

where:
 * is the number of the line on the tableau proof where Double Negation Introduction is to be invoked
 * is the pool of assumptions (comma-separated list)
 * is the statement of logic that is to be displayed in the Formula column, without the  delimiters
 * is the line of the tableau proof upon which this line directly depends
 * is the (optional) comment that is to be displayed in the Notes column.