Logical OR

Welcome! This is a lesson in the Introductory Discrete Mathematics for Computer Science course here at Wikiversity.

Previous lesson: Logical AND

The Disjunction
I apologize for the name of this lesson. The true name of this operator, which is a diadic operator, is a disjunction. It is sometimes called the inclusive OR operator, to distinguish it from another operator you'll learn about later. However, it is a bit dangerous to refer to a disjunction as an OR operator, because English words are far more vague than logic.

$$\vee$$ : This is the disjunction, a.k.a. the (inclusive) OR operator
 * Let $$p$$ represent the statement: It is raining.
 * Let $$q$$ represent the statement: I am hungry.
 * $$p \vee q$$ represents the disjunction of statements $$p$$ and $$q$$: It is raining OR I am hungry (OR it is raining AND I am hungry).

Truth Table for the Disjunction
This is its truth table:

Next Lesson
The name of the next lesson is Logical XOR.