Sujet : Re: How many different unit fractions are lessorequal than all unit fractions? (repleteness)
De : james.g.burns (at) *nospam* att.net (Jim Burns)
Groupes : sci.mathDate : 20. Sep 2024, 18:51:38
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <50cce993-5040-496a-822c-7f5d6558c22b@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
User-Agent : Mozilla Thunderbird
On 9/19/2024 12:29 AM, Ross Finlayson wrote:
On 09/18/2024 01:51 PM, Ross Finlayson wrote:
On 09/18/2024 12:37 PM, Chris M. Thomasson wrote:
[...]
>
Put pencil to paper and draw a straight line,
each of the points were encountered in order.
No matter how fine it's sliced, ....
>
Sometimes called "Hilbert's Postulate of Continuity".
Which he says is required, ....
Put pencil to paper and draw two curves which cross.
There is a point at which the curves intersect.
That is the Intermediate Value Theorem,
which can prove and from which can be proved
the Least Upper Bound Property.
That is what.we.mean.by line.
⎛ The line ℝ includes rationals ℚ
⎜
⎜ For each split S of ℚ,
⎜ if there isn't a rational qₛ at S
⎜ then there is an irrational rₛ at S
⎜
⎜ Each rational and irrational is at a split.
⎝
⎛ ℝ z ℚ
⎜
⎜ ∀S ⊆ ℚ: {} ≠ S ᵉᵃᶜʰ<ᵉᵃᶜʰ ℚ\S ≠ {} ⇒
⎜⎛ ¬∃qₛ ∈ ℚ: S ᵉᵃᶜʰ≤ qₛ ≤ᵉᵃᶜʰ ℚ\S ⇒
⎜⎝ ∃rₛ ∈ ∁ℚ: S ᵉᵃᶜʰ< rₛ <ᵉᵃᶜʰ ℚ\S
⎜
⎜ ℝ = ℚ ∪ ∁ℚ
⎜
⎜ ∀r ∈ ℝ: ∃Sᵣ ⊆ Q:
⎝ {} ≠ Sᵣ ᵉᵃᶜʰ< r ≤ᵉᵃᶜʰ ℚ\Sᵣ ≠ {}