Logical OR

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.

[math]\vee[/math] : This is the disjunction, a.k.a. the (inclusive) OR operator

Let [math]p[/math] represent the statement: It is raining.

Let [math]q[/math] represent the statement: I am hungry.

[math]p \vee q[/math] represents the disjunction of statements [math]p[/math] and [math]q[/math]: 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:

[math]p \,\![/math]	[math]q \,\![/math]	[math]p \vee q[/math]
T	T	T
T	F	T
F	T	T
F	F	F

Next Lesson

The name of the next lesson is Logical XOR.