Question

State true or false:

Statement: We cannot use Ogden’s lemma when pumping lemma fails.

(a) Statement: We cannot use Ogden’s lemma when pumping lemma fails.

(b) true

(c) false

The question was posed to me in an interview for internship.

My question is taken from Pumping Lemma for Context Free Language in division Properties of Context Free Languages of Automata Theory

Answer 1

The correct answer is (b) true

For explanation: Although the pumping lemma provides some information about v and x that are pumped, it says little about the location of these substrings in the string t. It can be used whenever the pumping lemma fails. Example: {a^pb^qc^rd^s|p=0 or q=r=s}, etc.