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