Am Freitag, 17. Januar 2020 07:33:59 UTC+1 schrieb Zelos Malum:
> >That is true for dark numbers only. Counting is easy for definable or countable numbrs.
>
> It is not relevant here bceause we are not doing counting you imbecile.
>
> >What is the sum of all natural numbers?
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> You cannot sum the set of all natural numbers,
But we can sum all definable natural numbers.
> but you can sum any of the natural numbers, or sum any finite subset of natural numbers.
And why is that so? Because any of the natural numbers that can be defined is definable. And any finite set must have a last definable natural number. But the set of all natural numbers consists mainly of undefinable natural numbers. Therefore it cannot be summed.
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> >Here we deal with natural numbers only.
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> We are not counting IN natural numbers
Never they have been counted.
> your argument is about CARDINALITY which means we are doing CARDINAL arithmetic, not natural number arithmetic!
Fo definable natural numbers we have appropriate arithmetic with natural numbers.
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> >The elements of endsegments of natural numbers are natural numbers by definition.
>
> Yes, but the cardinality, hwich is the one you go on about, is not natural numbers.
That is irrelevant. We know that for every definable endsegment
∀k ∈ ℕ: ∩{E(1), E(2), ..., E(k)} = E(k) /\ |E(k)| = ℵo
and for all endsegements
∩{E(1), E(2), E(3), ...} = { }
and for all endsegments the cardinalities obey
|E(k+1)| = |E(k)| - 1
This can never reach 0 without having passed ...3, 2, 1 before. Simplest arithmetic of finite numbers.
Regards, WM