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Re: Cantor Diagonal Proof

From Julio Di Egidio <julio@diegidio.name>
Newsgroups sci.math
Subject Re: Cantor Diagonal Proof
Date 2025-10-22 17:17 +0200
Organization A noiseless patient Spider
Message-ID <10dasho$mjcq$1@dont-email.me> (permalink)
References <vsn1fu$1p67k$1@dont-email.me> <10dajcd$j82n$1@dont-email.me> <10dam7c$lah6$1@dont-email.me> <10darmp$n85d$1@dont-email.me>

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On 22/10/2025 17:02, Tristan Wibberley wrote:
> On 22/10/2025 14:29, Richard Heathfield wrote:
>> On 22/10/2025 13:40, Tristan Wibberley wrote:
> 
>> Cantor's diagonal argument proves that uncountable sets exist. At no
>> point did he claim that the number the argument computes is incomputable.
>>
>>> I'm still unconvinced that he successfully [even defined the crucial number].
>>
>> He didn't try. An existence proof doesn't have to define a number.
> 
> True. I was being loose. It would have to construct every list itself.

That's not true, it's actually wrong.  See my previous reply.

Julio

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Thread

Re: Cantor Diagonal Proof Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-22 13:40 +0100
  Re: Cantor Diagonal Proof Richard Heathfield <rjh@cpax.org.uk> - 2025-10-22 14:29 +0100
    Re: Cantor Diagonal Proof Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-22 16:02 +0100
      Re: Cantor Diagonal Proof Julio Di Egidio <julio@diegidio.name> - 2025-10-22 17:17 +0200
      Re: Cantor Diagonal Proof Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-22 17:26 +0100
    Re: Cantor Diagonal Proof WM <wolfgang.mueckenheim@tha.de> - 2025-10-23 16:51 +0200
  Re: Cantor Diagonal Proof Julio Di Egidio <julio@diegidio.name> - 2025-10-22 16:19 +0200
    Re: Cantor Diagonal Proof Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-22 17:32 +0100
    Re: Cantor Diagonal Proof WM <wolfgang.mueckenheim@tha.de> - 2025-10-23 16:56 +0200
      Re: Cantor Diagonal Proof: un-_Countable_ or un-_Cartesian_? Ross Finlayson <ross.a.finlayson@gmail.com> - 2025-10-23 12:27 -0700
  Re: Cantor Diagonal Proof "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2025-10-22 12:15 -0700
  Re: Cantor Diagonal Proof wm <wolfgang.mueckenheim@tha.de> - 2025-10-23 16:34 +0200
    Re: Cantor Diagonal Proof Tristan Wibberley <tristan.wibberley+netnews2@alumni.manchester.ac.uk> - 2025-10-23 20:43 +0100
      Re: Cantor Diagonal Proof WM <wolfgang.mueckenheim@tha.de> - 2025-10-24 22:35 +0200

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