*HourIntervalFn* | *documentation* A BinaryFunction that maps two numbers to the Class of TimeIntervals that begin at the hour corresponding to the first number *and* that end at the hour corresponding to the second number. For example, (*HourIntervalFn* 6 12) returns the set of TimeIntervals that begin at 6 AM every day *and* that end at 12 noon every day. If necessary, we will define other interval functions for seconds, minutes, days, *and*/or months | |

**has axiom** (=> (*instance* ?INTERVAL (*HourIntervalFn* ?NUMBER1 ?NUMBER2)) (*and* (*lessThan* ?NUMBER1 24) (*lessThan* ?NUMBER2 24) (*lessThan* ?NUMBER1 ?NUMBER2)))
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**has domain1** PositiveRealNumber | |

**has domain2** PositiveRealNumber | |

**has ***range* TimeInterval | |

**is an ***instance* of BinaryFunction | |

**is an ***instance* of TemporalRelation | |

BinaryFunction | **is first ***domain* of *distributes* | |

**is first ***domain* of *identityElement* | |

**is second ***domain* of *distributes* | |

Class | **is third ***domain* of *domain* | |

**is third ***domain* of *domainSubclass* | |

Abstract | **is ***disjoint* from Physical | |