Consider the following language: L1 = ({0} {1}){0}{1}({0} {1}).

This language is the language of all strings over {0, 1} that contain 01 as a substring. Notice that L1 is expressed using the regular operations (union, concatenation, and Kleene star), and the languages {0}, {1}, {}, and .

(a) Let L2 be the language of all strings over {0, 1} wherein all occurrences of the 0 symbol occur in consecutive groups of two or more 0s. Express L2 using the regular operations and the languages {0}, {1}, {}, and .

(b) Let L3 be the language of all strings over {0, 1} that do not contain the substring 101. Express L3 using the regular operations and the languages {0}, {1}, {}, and .