Question

Let L be the language over {a,b,c} accepting all strings so that: 1. No b's occur before the first c. 2. No a's occur after the first c. 3. The last symbol of the string is b. 4. Each b that is not the last symbol is immediately followed by at least two c's. Choose any constructive method you wish, and demonstrate that Lis regular. You do not need an inductive proof, but you should explain how your construction accounts for each rule.

Choose any constructive method you wish, and demonstrate that L is regular. You do not need an inductive proof, but you should explain how your construction accounts for each rule.

Answer 1

Regular Expression

a*c(c + bcc)*b

Explanation

1. Before first c, only a's come optionally - a*
2. So, a's come jsut before the first c
3. ___b is the string
4. bccc* is there in the regular experssion

If a language has a regular expression, then the language is regular.

a* is for the first and second points
There should be one c at least because there is b at the end

(c + bcc)* for fourth point

3 is for last b

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