Logic: Boolean Laws

About This Unit

Boolean laws are rules used to simplify boolean expressions. Boolean expressions are written using boolean symbols, which can be broken down and represented visually with truth tables. In order to understand the purpose and function of boolean laws, we must first understand the basic symbols and their meanings as well as how they can be used to construct truth tables.



Boolean Symbols





NOTE: in the problem 6 solutions video, when I went over the distributive property, I should've pointed at the last and operator, not the operator between A and not B

Summary

Symbol Meaning
p,q Statements
T True
F False
AND
OR
¬ NOT
Equivalence


Truth Tables





NOTE: in the problem 6 solutions video, when I went over the distributive property, I should've pointed at the last and operator, not the operator between A and not B

Summary

p q p∧q
T T T
T F F
F T F
F F F
p q p∨q
T T T
T F T
F T T
F F F
p ¬p
T F
F T


Boolean Laws

Practice





NOTE: in the problem 6 solutions video, when I went over the distributive property, I should've pointed at the last and operator, not the operator between A and not B

Summary

  • Commutative: p ∨ q ≡ q ∨ p; p ∧ q ≡ q ∧ p
  • Associative: (p ∨ q) ∨ r ≡ p ∨ (q ∨ r ); (p ∧ q) ∧ r ≡ p ∧ (q ∧ r )
  • Distributive: p ∨ (q ∧ r ) ≡ (p ∨ q) ∧ (p ∨ r ); p ∧ (q ∨ r ) ≡ (p ∧ q) ∨ (p ∧ r )
  • Identity: p ∧ T ≡ p; p ∨ F ≡ p
  • Complement: p ∧ ¬p ≡ F ; p ∨ ¬p ≡ T
  • Annihilator: p ∧ F ≡ F ; p ∨ T ≡ T
  • Idempotence: p ∧ p ≡ p; p ∨ p ≡ p
  • Absorption: p ∧ (p ∨ q) ≡ p; p ∨ (p ∧ q) ≡ p
  • Double negation: ¬(¬p) ≡ p
  • De Morgan’s: ¬(p ∧ q) ≡ ¬p ∨ ¬q; ¬(p ∨ q) ≡ ¬p ∧ ¬q