16.2.1. Definition of Relation

Try these first

1. 1.

   Define a relation in your own words.

   Hint

   Think of connections between cities and their respective countries.

2. 2.

   What does it mean for a relation to be a subset?

   Hint

   Look for a smaller group within a larger group.

3. 3.

   What is a relation?

   • A set of numbers
   • A subset of Cartesian products
   • An ordered list

   Hint

   Think of how we connect elements from two sets.

4. 4.

   True or False: A relation can only exist between two different sets.

   • True
   • False

   Hint

   Consider an example where elements relate to themselves.

5. 5.

   Given sets A = {a, b, c} and B = {1, 2}, write all possible pairs in AxB and form a relation including at least one subset.

   Hint

   List all pairs then select some to form a relation.

6. 6.

   If a relation from A to B is given as R = {(1, 2), (2, 3)}, explain why it is not reflexive.

   Hint

   Check for self-relating pairs in the definition.