GATE 2001

Question 3

Consider two well-formed formulas in prepositional logic

   F1: P ⇒ ¬P          F2: (P⇒¬P)∨(¬P⇒P)

Which of the following statements is correct?

A	F1 is satisfiable, F2 is valid
B	F1 unsatisfiable, F2 is satisfiable
C	F1 is unsatisfiable, F2 is valid
D	F1 and F2 are both satisfiable

Question 3 Explanation:

F1 is satisfiable; F2 is valid.

Correct Answer: A

Question 3 Explanation:

F1 is satisfiable; F2 is valid.