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Logical OR

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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.