**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 left-recursive and equivalent to the CFG S --> Sab | Sbc | aSb | c (7) (10 pts) Given the CFG, G, given below, find a lambda-free CFG, G', such that L(G')=L(G)-{lambda}. S --> abSbScSd | lambda...

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- Spring '08
- varies
- Regular expression, Regular language, Nondeterministic finite state machine, Automata theory