# 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:

$p\,\!$ $q\,\!$ $p\vee q$ T T T
T F T
F T T
F F F

## Next Lesson

The name of the next lesson is Logical XOR.