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Unformatted text preview: s and there is nothing on the stack, then it accepts. If there are any b’s on the stack still, then this case fails. If one or both of each case pass, then it accepts, if either of them fail then it rejects. Problem 4 Give a counterexample to show that the following construction fails to prove that the class of CFL’s is closed under star. Let A be a CFL that is generated by the CFG G = (V, ∑, R, S). Add the new rule S SS and call the resulting grammer G’. This grammer is supposed to generate A*. S SS ⇒ that any language that follows this rule would ne...
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 Spring '10
 Roberts

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