Introduction:
In set theory, a Venn diagram is a visual representation of sets and their relationships. It consists of circles or other closed curves that represent sets, with overlapping regions indicating common elements between sets. Venn diagrams are commonly used to illustrate set operations such as union, intersection, and complement.

A-B Set:
Let's consider two sets A and B. The set A-B, also known as the relative complement of B in A, consists of elements that are in set A but not in set B. In other words, it represents the elements that are exclusive to set A and do not overlap with set B.

Disjoint Sets:
Disjoint sets are sets that have no elements in common. If two sets A and B are disjoint, then their intersection is an empty set (∅). In other words, A ∩ B = ∅. Disjoint sets can be represented using a Venn diagram by drawing separate circles for each set with no overlapping regions.

Venn Diagram for A-B Set:
If there are no common elements in the A-B set, it means that A and B are disjoint sets. Therefore, we can draw a Venn diagram for this scenario.

To represent the A-B set in a Venn diagram:
1. Draw a circle to represent set A.
2. Draw a separate circle to represent set B.
3. Ensure that there is no overlapping region or intersection between the two circles, indicating that the sets are disjoint.
4. Label the circles as A and B, respectively.
5. If needed, label the elements or provide additional information about the sets.

Example:
Let's consider an example to illustrate this concept:
A = {1, 2, 3}
B = {4, 5, 6}

Since there are no common elements between sets A and B, we can draw a Venn diagram for the A-B set as follows:
- Circle A: {1, 2, 3}
- Circle B: {4, 5, 6}

In this diagram, there is no intersection or overlapping region between the circles, indicating that the sets are disjoint.

Conclusion:
In conclusion, if there are no common elements in the A-B set, we can draw a Venn diagram to represent the disjoint sets. The Venn diagram visually illustrates the relationship between sets A and B, where there is no overlap or intersection. This representation helps in understanding the concept of disjoint sets and their relative complement.