Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail
From: Ben Bacarisse <ben@bsb.me.uk>
Newsgroups: sci.logic
Subject: Re: Simple enough for every reader?
Date: Mon, 02 Jun 2025 02:56:03 +0100
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WM <wolfgang.mueckenheim@tha.de> writes:
(AKA Dr. Wolfgang Mückenheim or Mueckenheim who teaches "Geschichte
des Unendlichen" and "Kleine Geschichte der Mathematik" at Technische
Hochschule Augsburg.)

> On 31.05.2025 02:20, Ben Bacarisse wrote:
>> WM <wolfgang.mueckenheim@tha.de> writes:
>
>>> It has been shown to the student by many arguments that the bijection
>>> fails.
>> Which of the conditions of being a bijection (as presented in your book)
>> does b fail to meet?  (I'm betting you won't say.)
>
> The condition to be definable.

There are two conditions (as you know perfectly well) and it meets both
(as you also know perfectly well).  Here are the conditions:

  bijektiv (oder eineindeutig), wenn f injektiv und surjektiv ist

Is b not injective?  Is b not surjektiv?  Here's b again so you can
check for yourself that it is both:

   b(0) = 1
   b(n+1) = s(b(n))
   where s(q) = 1 / (2*floor(q) - q + 1)

>> ...
>>> Without giving one of these arguments (if desired also showing that and why
>>> it fails) you would get only half of the full score.
>> You called me a liar for saying this.  I /would/ actually have to accept
>> the nonsense you teach (or at least copy it out) to get full marks.
>
> You could also disprove it. But you carefully evade.

Eh?  You just told me that what I wrote would not get full marks.  I
would have to parrot at least some of your nonsense to get more.  That's
all I was saying before when you said I was lying.

>> ...
>>>>>> Do you not have to write marking schemes for your exams?  And if in
>>>>>> fact you do, what do yours say about alternative answers?
>>>>
>>> If a student had ever disproved my proofs he would have got additional
>>> points.
>> Do you always refuse to answer simple questions?  Do you have to write
>> marking schemes for your exams?  I'm just trying to find out if there is
>> documentary evidence of what a student at your college has to write to
>> get full marks.

You really don't want to say, do you?

> Either understand and repeat what I teach or disprove it...

Exactly.  So why did you say I was lying?

By the way, I can see why you don't want to show any marking scheme.  It
would have to include the junk you expect the students to say, but with
a caveat "or the student can include a proof that Cantor was right, but
a correct proof better than Cantor's, or Church's or any of the others
that have been published up to now".  In the UK, that would be framed
and pinned to the common room wall!

-- 
Ben.