Unformatted text preview: # ”; strings with more than one “ # ” are don’tcare inputs that can be ignored to simplify the design of your PDA. Exercise 3. Show the intersection of a contextfree language C with a regular language R is always contextfree. Exercise 4. Show that the language { n 1 m n 1 m  n ≥ } is not contextfree. Exercise 5. Show that the language { ww  w ∈ ( + 1 ) * } is not contextfree. Hint: Intersect with * 1 * * 1 * and use the results from Exercises 3 and 4. Exercise 6 (bonus). Is the following language contextfree? Prove your answer. { ww  w ∈ ( a + b ) * , w ∈ ( a + b ) * , w 6 = w , and  w  =  w } Page 1...
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 Spring '09
 EdmundM.Clarke
 Formal language, Formal languages, ContextFree Grammars

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