Question

Let for ∑= {0,1} R= (∑∑∑) *, the language of R would be

(a) {w | w is a string of odd length}

(b) {w | w is a string of length multiple of 3}

(c) {w | w is a string of length 3}

(d) All of the mentioned

This question was posed to me in a national level competition.

Question is from Building Regular Expressions in division Regular Expressions and Languages of Automata Theory

Answer 1

The correct choice is (b) {w | w is a string of length multiple of 3}

Best explanation: This regular expression can be used to eliminate the answers and get the result. The length can be even and as well more than 3 when R= (∑∑∑) (∑∑∑) (particular case).