is a set | { } | |

is an element of | ∈ | |

is not an element of | ∉ | |

subset | is a subset of | ⊆ |

proper subset | is a proper subset of | ⊂ |

is not a subset of | ⊄ | |

union | ∪ | |

intersection | ∩ | |

the empty set | ∅ | |

proper superset | is a superset of | ⊇ |

superset | is a proper superset of | ⊃ |

Venn Diagram f(1) = 1 f(2) = 3 f(3) = 7 f(4) = 15 formula: f(1) = 1 f(n) = f(n-1) * 2 + 1