Nikolai vdB schrieb am Donnerstag, 28. Oktober 2021 um 17:06:54 UTC+2:
> WM schrieb am Mittwoch, 27. Oktober 2021 um 11:53:40 UTC+2:
> > > > Modern mathematics is not based upon completeness of bijections?
> > No answer.
> > > > >
> > > > > Fact is: Your "symmetry" is not necessary to prove a bijection,
> > > > It is valid and it turns out necessary. Do you think that it is invalid?
> > No answer.
> > I emphasized several times that I only show that one special mapping, which over decades had been believed to be a bijection, provably is not a bijection if
> > {1, 2, 3, 4, 5, ...} --> {1/1, 2/1, 3/1, 4/1, 5/1, ...}
> > is a bijection, and
> > {1, 2, 3, 4, 5, ...} --> {1/1, 2/1, 3/1, 4/1, 5/1, ..., M}
> > is not a bijection.
> >
> > That is the present topic! Can you agree to the last statement, where the pairs of the mappings are taken from left to right?
> No. Where is your definition of "completeness" from? Certainly not from modern mathematics. Certainly, bijective is not defined by any kind of 'completeness', but by being surjective and injective.
Surjective is only another word for complete.
> The function i gave you satisfies the definition of injective, anything about 'completeness' you make up is not part of real mathematics.
Surjectivity is required. Here
{1, 2, 3, 4, 5, ...} --> {1/1, 2/1, 3/1, 4/1, 5/1, ...}
the function f(n) = n/1 is surjective.
Here
{1, 2, 3, 4, 5, ...} --> {1/1, 2/1, 3/1, 4/1, 5/1, ..., M}
it is not surjective if M stands for other fractions than n/1.
>
> mathematical thoroughness,
Will certainly support this argument:
If {1, 2, 3, 4, 5, ...} --> {1/1, 2/1, 3/1, 4/1, 5/1, ..., M} is not surjective, then
{1, 2, 3, 4, 5, ...} --> {1/1, 1/2, 2/1, 1/3, 3/1, 1/4, 2/3, 3/2, 4/1, 1/5, 5/1, 1/6, ..., M} will not be surjective either.
Regards, WM