The disjunction of two propositions P and Q is the proposition that is true if at least one of the two propositions P and Q is true, and false if the two propositions are false.
Symbol
The disjunction of the propositions P and Q is noted as “P ∨ Q” and is read as “P or Q”.
Property
The truth table of a logical disjunction is:
| P | Q | P ∨ Q |
| 1 | 1 | 1 |
| 1 | 0 | 1 |
| 0 | 1 | 1 |
| 0 | 0 | 0 |
In which 1 = true and 0 = false.
Logical conjunctions and logical disjunctions are connected by the De Morgan laws.
¬(P∧Q) ⇔ ¬P∨¬Q
¬(P∨Q) ⇔ ¬P∧¬Q