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 : 19. Sep 2024, 19:02:54
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <9892944b-25f1-40c1-a978-bd5856d7a7af@att.net>
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User-Agent : Mozilla Thunderbird
On 9/19/2024 1:29 PM, Jim Burns wrote:
On 9/19/2024 12:29 AM, Ross Finlayson wrote:
[...]
>
ℝ is what.we.mean.by the continuum because
ℚ is gapless (ℚ does not 'next')
⎛ ¬∃q,q″ ∈ ℚ: q < q″ ∧
⎝ ¬∃q′ ∈ ℚ: q < q′ < q″
and ℝ completes ℚ
⎛ ¬∃S ⊆ ℚ: {} ≠ S ᵉᵃᶜʰ<ᵉᵃᶜʰ ℚ\S ≠ {} ∧
⎝ ¬∃r ∈ ℝ\ℚ: S ᵉᵃᶜʰ< r <ᵉᵃᶜʰ ℚ\S
I tried to simplify those expressions,
but I'm not convinced I got that right.
This is right:
⎛ ¬∃r,r″ ∈ ℝ: r < r″ ∧
⎝ ¬∃r′ ∈ ℝ: r < r′ < r″
⎛ ¬∃S ⊆ ℝ: {} ≠ S ≠ ℝ ∧
⎜ S ᵉᵃᶜʰ<ₑₓᵢₛₜₛ S ᵉᵃᶜʰ<ᵉᵃᶜʰ ℝ\S ∧
⎝ ¬∃r ∈ ℝ: S ᵉᵃᶜʰ< r ≤ᵉᵃᶜʰ ℝ\S
ℝ is gapless and complete.
such that
crossing ℝ×ℝ.curves intersect,
either in ℚ or in ℝ\ℚ
That is what I think is the motivation
for what.we.mean.by the continuum.