Save
...
Discrete Structures 1
Week 6 to 7
Logical Identities
Save
Share
Learn
Content
Leaderboard
Share
Learn
Created by
Marc
Visit profile
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)