From: Virgil on
In article
<67281815-918f-4f3d-85dd-674f22e6fb31(a)c10g2000yqi.googlegroups.com>,
WM <mueckenh(a)rz.fh-augsburg.de> wrote:

> Reason: Cantor either proves that a countable set is uncountable or
> that a constructible/computable/definable number is not constructible/
> computable/definable.

Cantor does non of those things.

WM tries to but does not succeed.
From: |-|ercules on
"WM" <mueckenh(a)rz.fh-augsburg.de> wrote
> On 16 Jun., 11:48, "|-|ercules" <radgray...(a)yahoo.com> wrote:
>> "WM" <mueck...(a)rz.fh-augsburg.de> wrote ...
>>
>>
>>
>> > By induction we prove: There is no initial segment of the (ANTI)diagonal
>> > that is not as a line in the list.
>>
>> Right, therefore the anti-diagonal does not contain any pattern of digits
>> that are not computable.
>>
> Sorry, you misquoted me. I wrote:
> By induction we prove: There is no initial segment of the diagonal
> that is not as a line in the list. And there is no part of the
> diagonal that is not in one single line of the list.


Sorry I thought you meant the anti-diagonal is computed to every finite prefix
as this is a more direct contradiction to any new sequences of digits being possible.

Herc
From: |-|ercules on
"WM" <mueckenh(a)rz.fh-augsburg.de> wrote
> On 16 Jun., 14:19, "J. Clarke" <jclarke.use...(a)cox.net> wrote:
>> On 6/15/2010 4:33 PM, WM wrote:
>>
>>
>>
>>
>>
>> > On 15 Jun., 21:38, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote:
>> >> WM says...
>>
>> >>> On 15 Jun., 18:53, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote:
>> >>>> For example, we can define a real r as follows:
>>
>> >>>> r = sum from n=0 to infinity of H(n) 2^{-n}
>>
>> >>>> where H(n) = 1 if Turing machine number n halts on input n,
>> >>>> H(n) = 0 otherwise.
>>
>> >>>> That's definable, but it is not computable.
>>
>> >>> Anyhow it is not a definition.
>>
>> >> It certainly is. It uniquely characterizes a real number,
>> >> so it's a definition.
>>
>> > It does not. If it would, the number could be computed.
>> > Who defines what Turing machine number n would do?
>>
>> Can you say "circular argument"? It's not a number because it's not
>> computable and that proves that all numbers are computable.-

It's darn well more logical definition than your superinfinity based on your
circular reasoning "no box contains the box numbers that don't contain their
own box number".

Oh but you have a backup proof, this is a new sequence because we *construct* it like so:

CANTORS PROOF
Defn: digit 1 is different, and digit 2 is different, digit 3 is different, ...
Proof: digit 1 is different, and digit 2 is different, digit 3 is different...
Therefore it's a different number!



>
> To be computable can be use as a *definition* of number.
> What is a natural number that cannot be counted or used for counting?
> What is a name that cannot be named?
> (A stone remains a stone, even if nobody names or knows it, but a
> thought that remains unthought forever is not a thought.)
> A real number could also be called a computable entity.
> Then we would earlier have recognized the charlatanism implicit in
> uncomputable or undefinable real "numbers".
> Cantor himself did not share that idea. He was convinced that the
> number of definition is not countable. Otherwise he was too much
> inclined to real mathematics to have upheld the claim of an
> uncountable set of reals.
>
> Regards, WM


We invented natural numbers, partitioned the space between natural numbers
recursively with one of ten options.

It's ridiculous to define a different number as "the other nine options ad infinitum".

Herc
From: Tim Little on
On 2010-06-15, Peter Webb <webbfamily(a)DIESPAMDIEoptusnet.com.au> wrote:
> No. You cannot form a list of all computable Reals. If you could do
> this, then you could use a diagonal argument to construct a
> computable Real not in the list.

You can form a list of all computable reals (in the sense of
mathematical existence). However, such a list is not itself
computable.


- Tim
From: Peter Webb on
>
> It is proof that there is no countable set of all real numbers, since
> any alleged such set is provably and constructably incomplete.
>
> Similarly, it is proof that there is no countable set of all
> constructable numbers, since any alleged such set is provably and
> constructably incomplete.

I hate to disagree with you, because we are on much the same "side", but
this is not correct. Cantor's proof shows that you cannot form a list of all
Reals. This is not the same as the Reals being uncountable.

You can use Cantor's diagonal construction to similarly prove that you
cannot form a list of all computable numbers. However the computable numbers
are in fact countable. You can't simply equate the two concepts; they are
not exactly the same thing.