The Math Forum



Search All of the Math Forum:

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


Math Forum » Discussions » sci.math.* » sci.math

Topic: Why do we need those real non-constructible numbers?
Replies: 59   Last Post: Nov 15, 2017 12:43 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Dan Christensen

Posts: 7,943
Registered: 7/9/08
Re: Why do we need those real non-constructible numbers?
Posted: Nov 9, 2017 8:33 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Thursday, November 9, 2017 at 1:54:32 AM UTC-5, WM wrote:
> Am Mittwoch, 8. November 2017 23:52:42 UTC+1 schrieb Dan Christensen:
>
>

> > > It convinces us of the fact that set theory can cause real brain damage. Of course you cannot be healed. But discussions like these are very helpful in convincing normal people including young students that set theory is really detrimental to clear thinking.
> >
> >
> > Brave words for someone who time and again has claimed to have found inconsistencies in set theory, but could not prove it in using the axioms of set theory as would be required.

>
> Axiom VII. The domain contains at least a set Z which contains the null-set as an element and is such that each of its elements a is related to another element of the form {a}, or which with each of its elements a contains also the related set {a} as an element.
>


You mean, the axiom of infinity? Usually stated as follows:

There exists set I: [Null in I & For all x in I: [x U {x} in I]]

where Null is the empty set.


> Axiom IV. Every set T is related to a second set ?(T) (the '"power set" of T), which contains all subsets of T and only those as elements.
>


Usually stated:

For all sets X: There exists set Y: For all Z: [Z in Y <=> For all w in Z: w in X]


> A model of a theory is a structure that satisfies the sentences of that theory, in particular its axioms.
>
> There is no countable model of axioms IV and VII.
>


There is nothing about "model" in the axioms of set theory (e.g. in ZFC). If you want to show that model theory is inconsistent, you will have to state the axioms of model theory and derive a contradiction using those axioms. Good luck with that. But then, you would STILL have to derive a contradiction using only the axioms of set theory which you have failed to do yet again, Mucke!


Dan

Download my DC Proof 2.0 freeware at http://www.dcproof.com
Visit my Math Blog at http://www.dcproof.wordpress.com









Date Subject Author
11/6/17
Read Why do we need those real non-constructible numbers?
bassam king karzeddin
11/6/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/8/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/9/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/9/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/9/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/9/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/9/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/13/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/14/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/14/17
Read Re: Why do we need those real non-constructible numbers?
genmailus@gmail.com
11/14/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/14/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/6/17
Read Re: Why do we need those real non-constructible numbers?
Stephen G. Giannoni
11/6/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/7/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/9/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
jsavard@ecn.ab.ca
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Jim Burns
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Jan Burse
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/8/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
bursejan@gmail.com
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Jan Burse
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Jan Burse
11/11/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/11/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/9/17
Read Re: Why do we need those real non-constructible numbers?
Tucsondrew@me.com
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/9/17
Read Re: Why do we need those real non-constructible numbers?
Tucsondrew@me.com
11/9/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/9/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/9/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/10/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/10/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/11/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/11/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/11/17
Read Re: Why do we need those real non-constructible numbers?
wolfgang.mueckenheim@hs-augsburg.de
11/8/17
Read Re: Why do we need those real non-constructible numbers?
Peter Percival
11/11/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/11/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com
11/15/17
Read Re: Why do we need those real non-constructible numbers?
bassam king karzeddin
11/15/17
Read Re: Why do we need those real non-constructible numbers?
Dan Christensen
11/15/17
Read Re: Why do we need those real non-constructible numbers?
zelos.malum@gmail.com

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2017. All Rights Reserved.