Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Matheology § 198
Replies: 40   Last Post: Jan 26, 2013 6:54 PM

 Search Thread: Advanced Search

 Messages: [ Previous | Next ]
 William Hughes Posts: 2,330 Registered: 12/7/10
Re: Matheology § 198
Posted: Jan 25, 2013 3:07 AM
 Plain Text Reply

On Jan 25, 8:57 am, WM <mueck...@rz.fh-augsburg.de> wrote:
> On 25 Jan., 08:41, William Hughes <wpihug...@gmail.com> wrote:
>
>
>
>
>
>
>
>
>

> > On Jan 25, 8:32 am, WM <mueck...@rz.fh-augsburg.de> wrote:
>
> > > On 25 Jan., 01:27, William Hughes <wpihug...@gmail.com> wrote:
>
> > > > On Jan 24, 8:52 am, WM <mueck...@rz.fh-augsburg.de> wrote:
>
> > > > > The following is copied from Mathematics StackExchange and
> > > > > MathOverflow. Small wonder that the sources have been deleted already.

>
> > > > > How can we distinguish between that infinite Binary Tree that contains
> > > > > only all finite initial segments of the infinite paths and that
> > > > > complete infinite Binary Tree that in addition also contains all
> > > > > infinite paths?

>
> > > > > Let k  denote the L_k th level of the Binary Tree.  The set of all
> > > > > nodes of the Binary Tree defined by the union of all finite initial
> > > > > segments (L_1, L_2, ..., L_k) of the sequence of levels U{0 ... oo}
> > > > > (L_1, L_2, ..., L_k) contains (as subsets) all finite initial segments
> > > > > of all infinite paths. Does it contain (as subsets) the infinite paths
> > > > > too?

>
> > > > > How could both Binary Trees be distinguished by levels or by nodes?
>
> > > > They cannot of course. Both have exactly the same levels and the same
> > > > nodes.

>
> > > > They can of course be distinguished.
>
> > > > In one case you do not include infinite subsets.
> > > > In the other you do.

>
> > > My question aimed at the posiibility to distinguish the Binary Trees
> > > by a mathematical criterion, namely that one that is applied in the
> > > diagonal argument. Of course you have understood that.

>
> > > That does not hinder you to believe in addition in matheological
> > > concepts that cannot be based on mathematical facts like nodes,
> > > levels, or digits.

>
> > Nope.  The concept is based on nodes, and levels.
>
> How do you express actual infinity by means of nodes or levels?
> Try it.
> Write a sequence like xxxxxxxxxx... and do never stop.
> Tell me when you have expressed an infinite sequence.

"Write a sequence like xxxxxxxxxx... and do never stop"

Perfectly acceptable finite description of an infinite sequence.

(Note we can now divide infinite sequences into two collections.
Those with finite descriptions, and those without finite
descriptions. Your approach is to consider the latter
collection as non existent)

© The Math Forum at NCTM 1994-2018. All Rights Reserved.