• RSemanticists candy (Re: Ordinals) [Addendum]

    From Mild Shock@21:1/5 to All on Mon Feb 26 13:01:44 2024
    I always thought all platonic realms are flooded with light!

    Now something from the formalists that want to
    to capture the light. It seems to me ordinals

    are a forgotten treasure. Nice papers here:

    W. A. Howard: Assignment of ordinals to terms for
    primitive recursive functionals of finite type.
    Howard, William A. (September 1970) https://www.sciencedirect.com/science/article/abs/pii/S0049237X08707705

    Systems of logic based on ordinals
    Alan Touring - 1938 (sic!) https://people.math.ethz.ch/~halorenz/4students/Literatur/TuringOrdinalLogic.pdf

    Homework for Dan Christensen:

    - Show PA consistent (in ZFC).

    WM schrieb:
    Le 22/02/2024 à 17:13, Jim Burns a écrit :
    On 2/22/2024 8:00 AM, WM wrote:
    Le 21/02/2024 à 18:59, Jim Burns a écrit :
    On 2/21/2024 3:33 AM, WM wrote:
    Le 20/02/2024 à 23:02, Jim Burns a écrit :

    Ordinals are well.ordered.

    Only those which can be specified.

    No.
    All of them are well.ordered.

    How do you know?

    In the same way that I know
    that right.triangles have three corners.

    Yes, you are right. I exaggerated. Having three corners is essential
    for triangles. Being well-ordered is essential for ordinals. What I
    meant is that we cannot follow the well-order into the dark realm. In particular Peano ceases.

    Regards, WM



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