Rainer Rosenthal schrieb am Donnerstag, 26. Januar 2023 um 20:26:54 UTC+1:
> Am 26.01.2023 um 09:40 schrieb WM:
> > Dann fasse Dir ein Herz und sei kein Esel, der meint, die ℵo undefinierbaren Stammbrüche einfach mit dem Schlachtruf "IA" oder "Quantorenvertauschung!" verschwinden lassen zu können.
> >
> Ach ja, danke für das Stichwort "Quantorenvertauschung". Dazu hattest Du
> ja kürzlich wieder herrlich konkreten Quatsch zusammengefaselt.
Nein, mein Lieber. Jeder, der glaubt, dies mit Quantorenvertauschung erklären zu können, ist ein absoluter Blindgänger. Das geschieht aber immer seltener, denn jeder noch nicht intellektuell pervertierte Student wird das keinem Lehrer abnehmen. Deswgen kommt jetzt die Unverständnis-Defensive. Um nicht einen neuen Thread anzufangen, was sich eigentlich geziemen würde, will ich hier einmal die Umtriebe de Salatmeisters Jürgen Rennenkampff zitieren, denn sie sind lesenswert. In sci.math verfasste er das folgende Salat-Meisterstück:
On Friday, January 27, 2023 at 11:10:04 AM UTC+1, WM wrote:
> Let us denote the Number of Unit Fractions existing between an object O on the positive real axis and zero as NUF_O.
>
> For the interval [1, 2], for instance, we find NUF_[1, 2] = ℵo.
> For the half-open interval (0, 1] we find NUF_(0, 1] = 0.
> But for every definable unit fraction 1/n we find NUF_1/n = ℵo.
>
> Since all unit fractions cover the interval (0, 1] but the definable unit fractions fail to cover it, we have a convincing proof of dark unit fractions in the vicinity of zero.
>
> The set has NUF 0. But this can only be checked by considering its elements because the point set is nothing more than its elements. For every considered point is fails. Hence not all points can be considered.
>
> A kinetic point of view: Move the cursor from 1 to 0 and note all unit fractions. When arriving at 0 you have passed ℵ₀ unit fractions in linear order. If they all were well-ordered, then you would have passed a last one (because no more are following). But you cannot determine which was the last one. That proves that most unit fractions are dark, i.e., not individually accessible.
>
> There is a point, namely zero, such that no unit fraction will follow. Hence there must have been a last one passed and a last one noted. Both cannot be identical because the last one noted has a finite number.
>
> Regards, WM
It's astonishing to what extent quackery in general, and Mückmeatical quackery in particular, depends upon neologisms and
undefined terms, as well is the misuse of the common vocabulary. For example, in the murky nonsense that Prof Dr. Mückenheim posted above,
almost every phrase is murky:
- number of (when more than finitely many)
- to be checked
- by considering
- considered point
- it fails
- an object O
- real axis (when neither naturals nor rationals exist in the usual sense)
- we find
- ℵo
- definable
- cover
- fail to cover
- dark
- dark unit fractions
- vicinity
some declarative sentences:
- The set has NUF 0
- can only be checked by considering its elements
- for every considered point it fails
- hence not all points can be considered
- cursor
- move
- note
- arriving at
- pass
- linear order
- well ordered
- last one
- no more are following
- you cannot determine
- that proves
- most unit fractions are dark
- individually accessible
- follow
- last one passed
- last one noted
- hence
- has a finite number
etc etc
That proves it: You cannot nail a pudding to the wall. But you can make a salad out of words.
Worauf ich nur lakonisch bemerkte:
> - number of (when more than finitely many)
erhalten wir nicht bloß eine einzige unendliche ganze Zahl, sondern eine unendliche Folge von solchen, die voneinander wohl unterschieden sind [Cantor]
You have never read Cantor? Or only never understood what you read, like my text here?
. . .
Bravo! Sure, you are a great salad master.
https://www.123rf.com/photo_131089519_chef-in-the-kitchen-of-the-hotel-or-restaurant-decorates-the-food-just-before-serving-.html?vti=mxxc23zbi9hrufqdgn-1-15
Regards, WM