P Q || P Q C | P | Q.................P Q || P Q C | Q | P
1..0....1..0..1....1...0.................0..1....0..1..1...1...0
.................X

Finally, we feed the values back into the strings. What we see in the valid pattern to the left is that we violate one of our truth-table rules when we attempt to do this (and we mark this with an X). In the invalid pattern to the right everything does fit, and we have found a bad line without having to do the entire truth table.

Either go back to where you started in testing for validity or go on for more complex examples.

Go back to the starting page.