Task 2

Question 1

The set of all alphabetic strings.

Answer 1

RE: /[a-zA-Z]+/

Question 2

The set of all lowercase alphabetic strings ending in a ‘b’.

Answer 2

RE: /[a-z]*b/

Question 3

The set of all strings with two consecutive repeated words (e.g., “Humbert Humbert” and “the the” but not “the bug” or “the big bug”).

Answer 3

RE: /\b(\w+)\s+\1\b/

Question 4

The set of all strings from the alphabet a,b such that each a is immediately preceded and immediately followed by a b.

Answer 4

RE: /(b+(ab+))+?/

Question 5

text:
ab
aba
abaabaab

Answer 5

RE: /(aba?)+/