• =?UTF-8?Q?Fwd:_Re:_Banach=e2=80=93Tarski_paradox?=

    From Ross Finlayson@ross.a.finlayson@gmail.com to sci.physics.relativity on Sun Oct 12 16:44:52 2025
    From Newsgroup: sci.physics.relativity




    -------- Forwarded Message --------
    Subject: Re: BanachrCoTarski paradox
    Date: Fri, 9 Feb 2024 16:47:57 -0800
    From: Ross Finlayson <ross.a.finlayson@gmail.com>
    Newsgroups: sci.logic
    References: <wtCdnWIVy5auHOrGnZ2dnUU7-X_NnZ2d@giganews.com> <uYCdnbuIathH8BzGnZ2dnUU7-c_NnZ2d@giganews.com> <7bd29ba6-1b6b-e62d-99ec-d6bdd40b2444@att.net> <Rr2dnU81IpB8hhnGnZ2dnUU7-UnNnZ2d@giganews.com> <539e30b6-a57f-44f4-9edb-d759b4470958@googlegroups.com> <EqOdnY-OGqk7-BjGnZ2dnUU7-bednZ2d@giganews.com>
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    On 09/04/2018 03:04 PM, Ross A. Finlayson wrote:
    On Tuesday, September 4, 2018 at 1:13:06 PM UTC-7, Ross A. Finlayson wrote:
    On Tuesday, September 4, 2018 at 8:51:32 AM UTC-7, Ross A. Finlayson wrote: >>> On Monday, September 3, 2018 at 10:41:40 PM UTC-7, peteolcott wrote:
    On 9/3/2018 1:03 PM, Ross A. Finlayson wrote:
    On Sunday, September 2, 2018 at 6:03:35 AM UTC-7, Peter Percival wrote: >>>>>> peteolcott wrote:
    On 8/31/2018 10:04 PM, exflaso.quodlibet@gmail.com wrote:

    From your own video, the number of points magically triples

    The number of points in the original sphere is equal to the sum of the >>>>>> number of points in the five pieces is equal to the sum of the number of >>>>>> points in the two spheres. That number is 2^aleph_0.

    by simply rotating this set of points. That is categorically
    impossible. My system of categorically exhaustive (thus
    infallible) reasoning caught that mistake.


    Remember it's not just "there's a bijective function however
    deranged it may be between sets of equal cardinality", but
    "using only rigid translations, Vitali splits all the points
    on [0,1] and would get a measure of 2 instead of 1, and where
    splitting as otherwise summatory or recursive preserves measure".



    I boil it down to much simpler than all that.
    If you remove a single point from a sphere and
    do not put it back it ceases to be a sphere.

    Copyright 2018 Pete Olcott

    Vitali and Hausdorff and later Banach and Tarski
    found some interesting "paradoxical" decompositions
    of "the points of the line", "paradoxical" meaning
    "established two ways not agreeing". Then the goal
    of logic for paradox is to resolve the paradox, to
    remove what must be some ambiguity or find what must
    be some truth about the objects that it is so.
    (Otherwise it's just erroneous not a "paradox".)

    So, talking about a "point in the line" or a "point
    on the line" is talking about two different things,
    two different "models" (or constructed entities) of
    what this "unit line segment" is. "Splitting all the
    points" is not the same thing as "partitioning a
    segment".

    I agree that the pointed (punctured) line is not
    the same as the line. Then that it's a "removable
    discontinuity" here is about Vitali making "removable
    discontinuities" all over one "continuous domain",
    that then the resulting "measure" in terms of a
    measure and a "measure 1.0" in particular, has that
    the measure of a resulting translation of the
    "removable discontinuities" preserves the measure.

    This then is usually that "these sets are non-measurable",
    or instead here that they illustrate features of points
    "in the line" (i.e., "all" the points) and "on the line"
    (i.e., "each" point).

    That this involves infinitesimals in the real numbers
    and about Veronese and Peano and standard infinitesimals,
    which are like Newton and Leibniz' differentials but that's
    only part of the story, this richer story of the infinitesimals
    finds more important features of their analytical character
    (real analysis).

    So, geometrically the punctured line looks different,
    but "splitting" all the points in the line is making
    two copies that fit exactly on the line (doubled).

    This is also phrased for a usual expectation
    that "measure is invariant" about what results
    as about a "quasi-invariant measure"

    https://en.wikipedia.org/wiki/Quasi-invariant_measure

    and here as from the examples about Lebesgue for the
    field continuity and Hausdorff for the line continuity
    (Lebesgue measure vis-a-vis Hausdorff measure) than
    in the quasi-invariant is in the example of Gaussian
    measure (as about usual centralizing tendencies in
    contrast to usual dispersive tendencies) and what
    conditions hold (or, don't) in the maintenance of
    invariant measure.

    That's an example of what's going on in "dynamical"
    measure theory and as discussed above about Brian and
    Oprocha and so on, and after Bergelson, about the ergodic
    and the Markov and non-Markov (but ergodic) basically
    gets into geometry having framed below, cardinals having
    framed above, now building that _in the various ways it has_
    to the middle.

    From Dr. Oprocha's publications, http://home.agh.edu.pl/~oprocha/?p=2 ,
    you can read a lot about what's going on the the research
    that's about analysis (and then what's for foundations to
    accommodate, i.e. the needful).

    This includes for example "re-Vitali-izing" the measure theory.

    The Wikipedia's quite grown these years and these days
    there's a page about the "Vitali covering lemma", and
    about Hausdorff and Lebesgue measure, and here in this
    context about differences between the areal and volumetric
    and what is density.

    https://en.wikipedia.org/wiki/Vitali_covering_lemma

    Here this usual notion of "removable discontinuity"
    is reflected in "negligeable collection" (or, negligible
    quantity).

    (Some tagged posts of T.Tao about measure and multiple
    recurrence:

    https://terrytao.wordpress.com/tag/lebesgue-measure/ https://terrytao.wordpress.com/tag/multiple-recurrence/ )



    Then, there is room for dispute of "The Vitali covering
    theorem is not valid in infinite-dimensional settings",
    as where it's framed as about the Gaussian instead of
    as we discuss here other relevant measures, in the
    infinite-dimensional setting. (And about a spiral-
    space-filling curve as finite- or infinite-dimensional.)


    There is much of this type of reasoning put to the
    van der Waerden theorem about arithmetic progressions
    much as an analog to Dirichlet/pigeonhole principle,

    https://en.wikipedia.org/wiki/Van_der_Waerden%27s_theorem

    except as a complement of how they disperse besides
    how they nest.

    "Van der Waerden's theorem is a theorem in the branch
    of mathematics called Ramsey theory."


    So, you can see that "re-Vitali-ization" is ongoing in
    mathematics writ large, and quite more accessibly these
    days then that as the dust arises of the construction,
    it all has to settle to the foundations again. Then,
    looking to "re-Vitali-ize" measure as from some quite
    fundamental notions as the spiral-space-filling curve
    and unique properties of the equivalency function (in
    continuity, analysis, differential analysis, singularity
    theory, and probability theory) makes a neat course for
    then laying out what are building up as these quite
    immense structures in categorical algebra in descriptive
    set theory, as somewhat neatly primitive (and accordingly
    fundamental).


    Wow, this is sounding kind of repetitive these days.



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  • From Ross Finlayson@ross.a.finlayson@gmail.com to sci.physics.relativity on Sun Oct 12 16:47:31 2025
    From Newsgroup: sci.physics.relativity




    -------- Forwarded Message --------
    Subject: Re: BanachrCoTarski paradox
    Date: Thu, 20 Sep 2018 19:45:15 -0700 (PDT)
    From: Ross A. Finlayson <ross.finlayson@gmail.com>
    Newsgroups: sci.logic
    References: <wtCdnWIVy5auHOrGnZ2dnUU7-X_NnZ2d@giganews.com> <EqOdnY-OGqk7-BjGnZ2dnUU7-bednZ2d@giganews.com>
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    On Thursday, September 20, 2018 at 9:01:38 AM UTC-7, wugi wrote:
    Op 19/09/2018 om 14:57 schreef Peter Percival:
    peteolcott wrote:


    It is categorically impossible and analogous to
    the circle with a missing point which is itself
    analogous to BanachrCoTarski.

    I once compared you unfavourably to Nam, and George Greene disagreed. I stand by my appraisal. At least Nam knows that proof counts in mathematics. He can't recognize a proof as being valid, and he couldn't produce one himself to save his life, but at least he knows that they
    are the gold standard. You, on the other hand, faced with a counter-intuitive result (in this thread Banach-Tarski) announce that it
    is categorically impossible. That it has been proved doesn't count for you, you just repeat "categorically impossible" like a parrot. Analogies furnish neither proofs nor refutations. (That analogies might guide someone towards a proof or a refutation is true, but that doesn't make analogies proofs or refutations.)

    And another thing - none of the newsgroups you are posting to is appropriate for a discussion about the Banach-Tarski paradox.

    This thread, if needs be, is a demonstration of BT, in the "sphere" of
    ideas: a statement (po's) even if infertile, can multiply itself out of nothing to as many clones as one wishes (or not wishes) :-o)

    So I don't see the end of it, unless people decide they've done their
    last bit :o

    --
    guido wugi

    Why feed the troll?

    If you're interested in Banach-Tarski (and including the
    original geometric besides the usual day's Banach-Tarski
    -Micielski or "the group-theoretic anagram") then one
    wonders why you don't investigate the today's modern
    Ramsey-type phenomena and otherwise what's going on
    in Borel vs. Combinatorics over uniform Cantor space,
    and dynamical measure theory and the new measure theory
    zoo and all, instead of "it's quite clear we use the
    countable additivity about measure 1.0 to keep that
    calculus remains sane and perfect".

    There's a reason for B-T and about Hausdorff and
    about Vitali in this dynamical measure theory that
    isn't just for weekend formalists.

    (And rather is for comprehensive, conscientious formalists.)




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