Every set can be well-ordered and you cannot convince me otherwise. AOC good.

  • hexaflexagonbear [he/him]
    ·
    4 years ago

    I hate the list of equivalent statements. Some are completely intuitive, others seem outlandish, but none seem like they should be related to eachother at all.

    • Puffin [any, they/them]
      hexagon
      ·
      4 years ago

      Honestly I'm pretty comfortable with most of the equivalent statements. Here are the statements I find especially intuitive:

      • The axiom of choice itself (the cartesian product of an infinite number of sets is non-empty)
      • Every surjective function has a right inverse
      • Trichotomy of set cardinality
      • Zorn's Lemma/Every vector space has a basis/Every ring has a maximal ideal/Every group has a maximal subgroup/Every connected graph has a spanning tree
      • Tychonoff's theorem
      • This one is equivalent to countable choice, but that a countable union of countable sets is countable
      • Well-ordering theorem

      Some of the weirder statements implied by it like Banach-Tarski/existence of non-Lebesgue measurable sets I just personally chalk up to general infinity weirdness in the same vein as something like Hilbert's Hotel.