What is the formal definition of a relation R between two sets A and B?

The video tests the less-than relation with two reversed ordered pairs: (2, 5) and (5, 2). It shows that $2 < 5$ is true, so the pair (2, 5) belongs to the relation.

Conditions: The relation is the less-than symbol (<) on integers.; The pairs tested are (2, 5) and (5, 2).

No, a relation does not have to contain every possible ordered pair. By definition, a relation is a subset of the Cartesian product $A \times B$, meaning it can include only some of the ordered pairs.

Conditions: A and B are sets.; R is a relation between A and B.

Ordered pairs are used because the order of the elements matters in a relation. The first component of the pair is related to the second component, and swapping them can change whether the relationship holds.

Conditions: The relation is between two sets A and B.; The relationship is directional or asymmetric.

In the definition of a relation, capital letters A and B denote the sets themselves, while lowercase letters a and b denote individual elements belonging to those sets. The ordered pair (a, b) represents a specific element of the Cartesian product $A \times B$, where a is an element of A and b is an element of B.

Conditions: The context is the formal definition of a relation R between sets A and B.; The notation (a, b) ∈ $A \times B$ is used.

Yes, elements of the sets can be left out of a relation. A relation is a subset of the Cartesian product, so it does not need to include every possible ordered pair.

Conditions: A relation R is defined between sets A and B.; R is a subset of $A \times B$.