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From: FromTheRafters <FTR@nomail.afraid.org>
Newsgroups: sci.math
Subject: Re: Incompleteness of Cantor's enumeration of the rational numbers
Date: Tue, 19 Nov 2024 11:42:12 -0500
Organization: Peripheral Visions
Lines: 56
Message-ID: <vhif57$1u588$1@dont-email.me>
References: <vg7cp8$9jka$1@dont-email.me> <vh2k9p$29cql$1@dont-email.me> <157a949d-6c19-4693-8cee-9e067268ae45@att.net> <vh35nd$2d81g$1@dont-email.me> <cb0c9917-09a9-45f0-8fe9-cd059fa82dde@att.net> <vh4itg$2o3vu$1@dont-email.me> <8165b44b-1ba5-429d-8317-0b043b214b53@att.net> <vh76bi$3bnde$1@dont-email.me> <d90452a5-965b-443f-9146-96cdf9b3906c@att.net> <vh8ft0$3jqb5$3@dont-email.me> <vh8g5e$3juug$1@dont-email.me> <vh8otd$3lhlt$2@dont-email.me> <vhb1is$6hbv$2@dont-email.me> <vhb1mu$6hbv$4@dont-email.me> <vhb32t$7ese$1@dont-email.me> <vhch7n$hge9$2@dont-email.me> <vhcieh$jjk5$1@dont-email.me> <vhcjg5$hdd4$3@dont-email.me> <vhckkh$k32g$1@dont-email.me> <vhcp0r$hge9$6@dont-email.me> <vhd7d7$nt37$1@dont-email.me> <vhd9lq$obb0$1@dont-email.me> <vhdl0k$qltl$1@dont-email.me> <vhfqcv$1adld$1@dont-email.me> <vhfso7$1bik6$1@dont-email.me> <vhg0h8$1adlc$4@dont-email.me> <vhgd9j$1eq8t$1@dont-email.me> <vhgebm$1eu67$2@dont-email.me> <vhgfo7$1f8j9$1@dont-email.me> <vhiak4$1sjsn$2@dont-email.me>
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WM submitted this idea :
> On 18.11.2024 23:40, FromTheRafters wrote:
>> WM wrote on 11/18/2024 :
>>> On 18.11.2024 22:58, FromTheRafters wrote:
>>>> on 11/18/2024, WM supposed :
>>>>> On 18.11.2024 18:15, FromTheRafters wrote:
>>>>>> WM brought next idea :
>>>>>
>>>>>>>> >ℕ| - |ℕ| = 0 because if you subtract one element from ℕ then you
>>>>>>>> have
>>>>>>> no longer ℕ and therefore no longer |ℕ| describing it.
>>>>>>
>>>>>> Still wrong.
>>>>>
>>>>> If you remove one element from ℕ, then you have still ℵo but no longer
>>>>> all elements of ℕ.
>>>>
>>>> But you do have now a proper subset of the naturals the same size as
>>>> before.
>>>
>>> It has one element less, hence the "size" ℵo is a very unsharp measure.
>>
>> Comparing the size of sets by bijection. Bijection of finite sets give you
>> a same number of elements, bijection of infinite sets give you same size of
>> set.
>
> Why? Because only potential infinity is involved. True bijections pr5ove
> equinumerosity.
>>>>> If |ℕ| describes the number of elements, then it has changed to |ℕ| - 1.
>>>>
>>>> Minus one is not defined.
>>>
>>> Subtracting an element is defined. |ℕ| - 1 is defined as the number of
>>> elements minus 1.
>>
>> Nope!
>
> The number of ℕ \ {1} is 1 less than ℕ.
>>
>>>>> If you don't like |ℕ| then call this number the number of natural
>>>>> numbers.
>>>>
>>>> Why would I do that when it is the *SIZE* of the smallest infinite set.
>>>
>>> The set of prime numbers is smaller.
>>
>> No, it is not.
>
> It is, because 4 and 8 are missing.
>
> > There is a bijection.
>
> Only between numbers which have more successors than predecessors, although
> it is claimed that no successors are remaining.
You are not making any sense.