# Collections

`Sequence`

The most primitive collection: a series of expressions.

MathJSON | LaTeX |
---|---|

`["Sequence", 1, 2]` |
\( 1 2 \) |

`["Sequence", ["Add", "x", 1], "y"]` |
\( x + 1 y \) |

`Set`

An unordered collection of unique elements.

MathJSON | LaTeX |
---|---|

`["Set", "x", "y"]` |
\( \lbrack x, y\rbrack \) |

`List`

An ordered collection of elements.

Use to represent a data structure, as opposed to `Parentheses`

or `Sequence`

.

MathJSON | LaTeX |
---|---|

`["List", "x", "y", "7", "11"]` |
\([x, y, 7, 11]\) |

`["List", "x", "Nothing", "y"]` |
\([x,y]\) |

`Delimiter`

One or more expressions in a sequence, enclosed with some delimiters and separated by a separator

Use to represent function arguments and to group arithmetic expressions.

MathJSON | LaTeX |
---|---|

`["Parentheses", ["Sequence", "x", "y", "7", "11"]` |
`(x, y, 7, 11)` |

`["Delimiter"]` |
`()` |

`["Delimiter", "a", "b", "c"]` |
`(a, b, c)` |