Sujet : Re: Incompleteness of Cantor's enumeration of the rational numbers (extra-ordinary)
De : james.g.burns (at) *nospam* att.net (Jim Burns)
Groupes : sci.mathDate : 13. Jan 2025, 21:44:10
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <309b1b88-6eca-4e27-b1d6-cd927203286f@att.net>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
User-Agent : Mozilla Thunderbird
On 1/13/2025 12:29 PM, WM wrote:
On 13.01.2025 18:06, Jim Burns wrote:
On 1/13/2025 7:48 AM, WM wrote:
On 13.01.2025 05:51, Moebius wrote:
Es gilt dann also |ℕ|/n = |ℕ|.
>
Wrong. |ℕ| is a fixed number.
>
By 'fixed', you mean that #ℕ > #(ℕ\{0})
>
However,
ℕ is the set of all 'fixed' (finite) ordinals.
>
Which is ivariable.
ℕ is only invariable in the sense which we use.
Nothing changes status from in.ℕ to not.in.ℕ,
or the other direction.
However,
you (WM) are convinced that
a set (such as ℕ) larger than
any set with sets.different.in.size.by.one
changes (has elements inserted or deleted)
in order to not.change.in.size.by.one.
ℕ does not change.
ℕ changing is not the reason that
there aren't sets.different.in.size.by.one
ℕ is larger than any of those sets.
Yes,
it would be very weird for a finite set
to be larger than any of those sets.
However, ℕ is not a finite set.
⎛ Assume ℕ is 'fixed'.
⎜
⎜ A 'fixed' ordinal ⟦0,𝔑⦆ the size of ℕ exists.
>
|ℕ| = ω-1.
No.
j < ω ⇒ j < j+1 < ω
j < k < ω ⇒ j ≠ ω-1
j < ω ⇒ j ≠ ω-1
⎜ #⟦0,𝔑⦆ = #ℕ
⎜
⎜ ⟦0,𝔑+1⦆ is 'fixed', too.
>
ω
Is ω = ⟦0,𝔑+1⦆ your 'fixed' (our 'finite')?
If ⟦0,𝔑⦆ is finite, then
⟦0,𝔑+1⦆, ⟦0,𝔑+2⦆, ⟦0,𝔑+3⦆ are finite.
What about ω+1 and ω+2?
⎜ ⟦0,𝔑+1⦆ ⊆ ℕ
>
No.
Yes.
𝔑 ∈ ℕ ⇔ finite ⟦0,𝔑⦆
finite ⟦0,𝔑⦆ ⇔ finite ⟦0,𝔑+1⦆
finite ⟦0,𝔑+1⦆ ⇔ 𝔑+1 ∈ ℕ
∀𝔑 ∈ ℕ: #⟦0,𝔑⦆ < #⟦0,𝔑+1⦆ ≤ #ℕ