# Prooftoys logic symbols quick reference

**Note:** the “plain text” forms are recognized in all kinds of input,
as when entering formulas through the keyboard.

Concept | English | Symbol | Text entry |
---|---|---|---|

Untrue | not | `not` |
not |

At least one true | or | `|` |
| |

Both true | and | `&` |
& |

Conditional | implies | `=>` |
=> |

Equivalent | `==` |
== | |

True for all | for all | `forall` |
forall |

True for some | exists | `exists` |
exists |