Lecture 13 Flashcards
1
Q
What does it mean for a logic formula to be ‘Valid’?
A
Every assignment will make the formula true.
2
Q
What does it mean for a logic formula to be a ‘Tautology’?
A
Every assignment will make the formula true.
This is also known as it being ‘valid’.
3
Q
What does it mean for a logic formula to be ‘Invalid’?
A
At least one assignment makes the formula false.
4
Q
What does it mean for a logic formula to be ‘Satisfiable’?
A
At least one assignment makes the formula true.
5
Q
What does it mean for a logic formula to be ‘Unsatisfiable’?
A
Every assignment makes the formula false.
6
Q
What makes two logic formulas X and Y ‘equivalent’?
A
When X Y is a ‘tautology’.
