(i) Chain rule

Ans: Chain Rule

P→ Q

Q→R/P →R

(ii) Simplification

Ans: (i) P∧Q/P and

( ii) P∧Q/Q

The rule says that if P ∧ Q is True then P can be assumed to be True ( and similarly

Q may be assumed to be True.)

Some of us may be surprised at the mention of the rule, thinking that if P∧ Q is True

then P must be True. The symbol ∧ is generally read as ‘and’. But the significance of

the rule is that ‘ ∧ ’ is merely a symbol and its meaning in the sense of ‘and’ comes

only through this rule of inference.