From: MoeBlee on
Virgil wrote:
> But, as I said, is about as non-existent as a string can get. Any less
> existent and it wouldn't be a string at all.

Okay, so there are degrees (degrees of more and of less) of existence?

MoeBlee

From: Tony Orlow on
Virgil wrote:
> In article <457d965d(a)news2.lightlink.com>,
> Tony Orlow <tony(a)lightlink.com> wrote:
>
>> Virgil wrote:
>>> In article <457cc0ce(a)news2.lightlink.com>,
>>> Tony Orlow <tony(a)lightlink.com> wrote:
>>>
>>>> I suppose now you're going to tell me I'm using nonstandard language....
>>> Almost always, as far as the meaning of standard mathematical terms goes.
>> Did you at least learn what a formal language is now? I remember you
>> taking issue with me about the "null string" as if no such thing
>> existed.
>
>
> Where pray tell did I ever do that?.
>
> Besides, in a sort of sense, isn't being a null string about as
> non-existent as a string can get?

The existence of the null string is uncontroversial, as opposed to the
existence of my uncountable T-riffic strings. :)
From: Tony Orlow on
Virgil wrote:
> In article <457d95fb(a)news2.lightlink.com>,
> Tony Orlow <tony(a)lightlink.com> wrote:
>
>>> Does TO claim that the infinite numbers of Robinson's non-standard
>>> analysis are in any way connected to the transfinite cardinals and
>>> ordinals of Cantor's analyses? Pray tell what ultrafilter generates
>>> standard cardinals and ordinals in the way that ultrafilters are needed
>>> to construct Robinson's non-standard reals from standard reals.
>> I claimed no such thing. I am saying his very reasonable approach
>> directly contradicts the very concept of the limit ordinals
>
> How does it do that? As there are n ordinals in his non-standard reals,
> and discussion of ordinality is irrelevant in his system.

Is omega considered the smallest infinite number? Omega then does not
exist in nonstandard analysis.
From: Tony Orlow on
Virgil wrote:
> In article <457D8AC9.5060306(a)et.uni-magdeburg.de>,
> Eckard Blumschein <blumschein(a)et.uni-magdeburg.de> wrote:
>
>> On 12/7/2006 1:27 AM, David Marcus wrote:
>
>>>> And which role has been envisioned for aleph_1?
>>> Kind of a silly question. aleph_1 is the first cardinal after aleph_0.
>>> That's its "role".
>> So far I was told aleph_1 means the continuum of the reals.
>
> Given the continuum hypothesis, it is. But that is not how it is
> defined, and absent the continuum hypothesis, one cannot say for
> certain.

CH says that c, the cardinality of the continuum, is equal to aleph_1,
the first cardinal after aleph_0. That simple question appears to be
undecidable, leaving open the possibility that aleph_1 is less than c.
From: MoeBlee on
Tony Orlow wrote:
> Is omega considered the smallest infinite number? Omega then does not
> exist in nonstandard analysis.

You'll have to define 'exist in non-standard analysis'. In the set
theory that is presupposed for the work of non-standard analysis, omega
exists. In classical mathematical logic that is the very hearth of
non-standard analysis, we suppose the existence of the set of natural
numbers. And in IST, omega exists.

You seem to have the mistaken impression that non-standard analysis is
some kind of mathematics that is separable from classical mathematics
and set theory.

MoeBlee