Logical Identities

Cards (14)

  • Logical identities are fundamental principles or equivalences that hold a truth value of true in logic.
  • Logical identities it is used to simplify and manipulate logical expressions.
  • Identity Laws
    • p ∧ True = p
    • p ∨ False = p
  • Domination Laws
    • p ∧ False = False
    • p ∨ True = True
  • Idempotent Laws
    • p ∧ p = p
    • p ∨ p = p
  • Commutative Laws
    • p ∧ q = q ∧ p
    • p ∨ q = q ∨ p
  • Associative Laws
    • (p ∧ q) ∧ r = p ∧ (q ∧ r)
    • (p ∨ q) ∨r=p∨(q∨r)
  • Distributive Laws
    • p ∧ (q ∨ r) = (p ∧ q) ∨ (p ∧ r)
    • p ∨ (q ∧ r) = (p ∨ q) ∧ (p ∨ r)
  • Complement / Inverse Laws
    • p ∧ ¬p = False (Contradiction Law)
    • p ∨ ¬p = True (Excluded Middle Law)
  • De Morgan's Laws
    • ¬(p ∧ q) = ¬p ∨ ¬q
    • ¬(p ∨ q) = ¬p ∧ ¬q
  • Absorption Laws
    • p ∨ (p ∧ q) = p
    • p ∧ (p ∨ q) = p
  • Double Negation Law
    • ¬(¬p) = p
  • Implication
    • p → q = ¬p ∨ q
  • Equivalence
    • p<->q = (p→q) ∧ (q→p)