1.4.4 Truth Tables Video
PROFESSOR: Just as truth tables provide a simple, direct way to define the meanings of the individual propositional connectives or propositional operators, they also provide a methodical way to understand the behavior of formulas, and in particular whether two formulas are equivalent or whether a formula is valid, meaning that it's always true. So let's take a look at that. To being with, if I'm thinking about a propositional formula that's a composite one that's built out of lots of more atomic, primitive ones, then in order to figure out the value of the whole thing, I need to know the values of the individual components. So if we think of a formula involving P's and Q's and R's that are true/false value propositional variables, then I need a truth assignment to know the values of those variables, in order to know whether or not the formula is true or false. So in computer science jargon, this process of assigning values to variables is c...