Unformatted text preview: Prove that L(P) U L(R) is a subset of L(P U R). (5) (10 pts) Prove that (making believe the *'s and .'s are superscripts) [ [ [ [a U b]* U a] . [a . b]] U c]* is a regular expression over the alphabet {a,b,c,d}. (6) (10 pts) Find a CFG which is not leftrecursive and equivalent to the CFG S > Sab  Sbc  aSb  c (7) (10 pts) Given the CFG, G, given below, find a lambdafree CFG, G', such that L(G')=L(G){lambda}. S > abSbScSd  lambda...
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 Spring '08
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 Regular expression, Regular language, Nondeterministic finite state machine, Automata theory

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