Answer and Explanation:
Solution: The operation of concatenation for a set of string on p. and the set is
AB = {XY | X ∈ A and y ∈ B}.
We need to satisfy all these following properties to find out the standard set is closed under concatenation.
1- Union of two standard sets also belongs to the classic collection. For example, A and B are regular. AUB also belongs to a regular group.
2- Compliment of two standards set A and B are A’ and B’ also belonging to the standard set.
3- Intersection of two standards set A and B is A∩B is also a regular set member.
4- The difference between two regular sets is also standard. For example, the difference between A and B is A-B is also a standard set.
The closure of the regular set is also standard, and the concatenation of traditional sets is regular.
