Valid Formula
A formula of a formal language is a valid formula if and only if it is true under every possible interpretation of the language. In propositional logic, they are tautologies.
Read more about this topic: Validity
Famous quotes containing the words valid and/or formula:
“Just as soon as we notice that someone has to force himself to pay attention when dealing and talking with us, we have a valid demonstration that he does not love us or that he does not love us anymore.”
—Friedrich Nietzsche (1844–1900)
““It’s hard enough to adjust [to the lack of control] in the beginning,” says a corporate vice president and single mother. “But then you realize that everything keeps changing, so you never regain control. I was just learning to take care of the belly-button stump, when it fell off. I had just learned to make formula really efficiently, when Sarah stopped using it.””
—Anne C. Weisberg (20th century)