# Utility Modules

Alloy 4 contains a number of utility modules that provide common operations on graphs, integers, etc. Here is a list of the modules and a short description for each module:

module util/boolean |
Creates a Bool type with two singleton subtypes: True and False. |

module util/graph[node] |
Utilities for common operations and contraints on graphs. |

module util/integer |
Utilities for using integers in Alloy. |

module util/natural |
Utilities for using the set of nonnegative integers (0, 1, 2, …). |

module util/ordering[element] |
Creates a single linear ordering over the atoms in elem. |

module util/relation |
Utilities for common operations and constraints on binary relations. |

module util/sequniv |
This module models each sequence of elements using a relation. (This module is imported automatically if your model uses the new seq keyword. |

module util/ternary |
Utilities for common operations and constraints on ternary relations. |