Let p and q be any two propositions. Consider the following propositional statements.

S1 : p → q
S2 : ¬ p ∧ q
S3 : ¬ p ∨ q
S4 : ¬ p ∨ ¬ q

where ∧ denotes conjunction (AND operation), ∨ denotes disjunction (OR operation), and ¬ denotes negation (NOT operation). Which one of the following options is correct?
(Note: ≡ denotes logical equivalence)

A.

S1 ≡ S3

B.

S2 ≡ S3

C.

S2 ≡ S4

D.

S1 ≡ S4

Solution:

Analyse Each Statement:

  • S1 : p → q ⇒ ¬ p q

  • S2 : ¬ p ∧ q (No direct simplification here)

  • S3 : ¬ p ∨ q (Matches S1 after simplification)

  • S4 : ¬ p ∨ ¬ q

On Compare: S1 ≡ S3