
Re: Cantor's first proof in DETAILS
Posted:
Nov 14, 2012 2:12 AM


On Nov 14, 12:45 am, "LudovicoVan" <ju...@diegidio.name> wrote: > "Zuhair" <zaljo...@gmail.com> wrote in message > > news:3929e6b62932401dba0a0a440bb18277@y6g2000vbb.googlegroups.com...> On Nov 13, 11:16 pm, Uirgil <uir...@uirgil.ur> wrote: > > <snip> > > >> Your alleged argument against the Cantor proof does not work against > >> either Cantor's proof, nor Zuhair's proof, nor my proof for that matter, > >> since your N* is irrelevant for all of them. > > > I showed in the Corollary that even if he use N* as the domain of > > (x_n), still we can prove there is a missing real from the range of > > (x_n). So Cantor's argument or my rephrasing of it both can easily be > > shown to be applicable to N* (any set having a bijection with N) as > > well as N. > > You are simply missing the point there: we don't need N* to disprove Cantor, > we need N* to go beyond it and the standard notion of countability. In > fact, that there is a bijection between N* and N is a bogus argument too, as > the matter is rather about different order types. > > LV
Now I think I'm beginning to somewhat perhaps understand your argument. I think (I'm not sure though) that what you want to say is that when we are having arguments with "LIMITS" then we must design the whole argument such that the Limit comes from the sequence, and if this design was not made then the argument is inherently deficient as far as the truth of inferences derived from it is concerned. So what you are trying to say is that Cantor's argument began with incomplete arsenal so it ended up with misleading inferences. You are making an argument at TRUTH level of the matter, and yet it is concerned with formal technicality as well, which is an argument beyond the strict formal technicality.
Anyhow if I'm correct, this form of reasoning for it to stand the quest, then there must be a clear line of justification for it. For instance the argument about whether the reals are countable actually means literally whether there is a bijection between the reals and N, so N is at the heart of the subject. Now to go and say that countability of the reals (which means bijectivity of reals to N) can only be reached about by circumventing N and using another countable infinite set N* as the domain for any sequence in an argument using limits is really strange somehow.
What you are having is the following:
[1]When we use N as the domain of injections (x_n), (a_n) and (b_n), then Cantors argument PROVES and SHOWS that there is a real that is not in the range of those functions.
[2]When we use N* as the domain of injections (x_n), (a_n) and (b_n), then Cantor's argument will seize from working in the same way to show the missing real.
[3]However we also have the corollary that even when we use N* as the domain of those functions, still we can by a single common well defined way define another sequence with exactly the same range of those functions but from domain N, and we can apply Cantor's argument and SHOW a missing real in the rang of those functions!
Now you call [1] deficient, [2] apt to reality standards [3] bogus.
Why? because we used N in an argument that involves a higher order concept that must use N* instead. (That's your reply).
But again: why? what is the higher order part of the argument that you see it demanding circumventing the heart of the subject (which is N really) to some N*.
Is it the definition of Limit.
But limit is defined in this argument as the least upper bound, and I don't see in the definition of L that I wrote (which is the standard by the way) anything that has to do with necessarily picking it up from some Omega_th end point? that has no meaning at all, so why?
Should I adopt this rational of yours then I'd ask you: why not say pick L from the 1_th starting point. i.e. choose your domain to be {1,0,1,2,3,...} since this clearly also preclude Cantor's argument and you clearly can make L be the 1_th digit of (x_n) [Remember a_0 is x_0, so x_{1} lies "before" a_0].
Or you'll say that {1,0,2,3,...} is also a kind of high order countable set?
Your argument is simply shunning one of the most important two sets in this argument, that is N, and using some replacement, without any clear justification.
Zuhair

