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On 06.02.2025 01:46, Jim Burns wrote:Which just means that no one FISON is needed to build the set of Natural Numbers, as there are always ones bigger.On 2/5/2025 2:18 PM, WM wrote:Why should we use two different writings?The axiom of induction:>
∀P( P(1) /\ ∀k(P(k) ==> P(k+1)) ==> ∀n (P(n)))
>
P(1): U(F(n) \ F(1)) = ℕ.
>
P(k): U(F(n) \ {F(1), F(2), ..., F(k)}) = ℕ
==>
P(k+1): U(F(n) \ {F(1), F(2), ..., F(k+1)}) = ℕ.
A description, not a magic spell.
>
...which could also be written...>it is proved that all F(n) can be subtracted like by induction all natural numbers can be subtracted from ℕ:>I can remove all FISONs from U(F(n))
without changing the claimed union.
What you (WM) mean by 'remove all...without changing..."
is that, by induction,
{1} can be subtracted because it is an element of in ℕ.
If {n} has been subtracted, then {n+1} can be subtracted because it is an element of in ℕ.
By the axiom of induction the result is the empty set.
Regards, WM
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