The disjunction of a set of subformulas is true if any of the subformulas are true.
The symbol we use for disjunction is ∨.
The disjunction of zero subformulas is trivially false.
The disjunction of a single subformula is equivalent to that subformula.
A
A ∨ ~A
A ∨ B ∨ C
The truth table below shows all possible combinations for a binary disjunction.
Here t stands for true, and f stands for false.
A | B | A ∨ B |
|---|---|---|
f | f | f |
f | t | t |
t | f | t |
t | t | t |
Doets, Kees. From Logic to Logic Programming. MIT Press, 1994.
Copyright © 2014 Barry Watson. All rights reserved.