A Relation R from A to B can be depicted pictorially using arrow diagram. In arrow diagram, we write down the elements of two sets A and B in two disjoint circles. Then we draw arrow from set A to set B whenever (a, b) ∈ R. An example of information depicted through an arrow diagram is shown below. For example:
A company has four categories of employees given by Assistants (A), Clerks (C), Managers (M) and an Executive Officer (E). The company provides ₹10,000, ₹25,000, ₹50,000 and ₹1,00,000 as salaries to the people who work in the categories A, C, M and E respectively. Here A1, A2, A3, A4 and A5 are Assistants; C1, C2, C3, C4 are Clerks; M1, M2, M3 are Managers and E1, E2 are Executive Officers then the relation R is defined by xRy, where x is the salary given to person y.
If the number of elements in set A and set B are p and q, then the number of relations from A to B are