Re: 2N=E

Am 08.11.2024 um 00:05 schrieb Moebius:

 >>>> For all n e IN:
 >>>>
 >>>>         1 + ... + n
 >>>>
 >>>> is a natural number (i.e. in IN).
 (Simple proof by induction.)

Proof (by induction):
1 is a natural number (Peano axiom).
If 1 + ... + n e IN (with n e IN), then 1 + ... + n + (n+1) e IN, since n+1 e IN if n e IN (Peano axiom and def. of addition) and m + n e IN if m,n e IN (->proof by induction). qed
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