Page 19 - Chapter 2

• Logically Follow

If an implication p ⇒ q is a tautology, where p and q may be

compound statements involving any number of proposition

variables, we say that q logically follows from p.

Suppose that an implication of the form (p1 ∧ p2 ∧… ∧ pn)

⇒ q is a tautology. We say that q logically follows from p1,

p2, …, pn, denoted by

(p 1 ∧ p 2 ∧… ∧ p n) ⇒ q

The p i’s are called the hypotheses or premises, and q is

called the conclusion.

Note: we are not trying to show that q is true, but only that q

will be true if all the p i are true.

∴ denotes “therefore”

 Rules of interface