I am reading a book called "The Haskell Road to Logic, Maths and Programming"
A question in the book is: "How many truth tables are there for 2-letter formula's"
The answer in the answer sheet is:
"A two-letter formula has a truth table with four rows. The value at every row can be either t of f, so there
2^4 = 16 truth tables altogether."
Now I don't understand, how a 2 letter formula, can have 16 truth tables?
P ⇒ Q
It will look like:
P Q (P⇒Q) T T T T F F F T T F F T
Now how can this have 16 tables? It looks like one table to me.