Drexel dragonThe Math ForumDonate to the Math Forum



Search All of the Math Forum:

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


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

Topic: UNCOUNTABILITY
Replies: 59   Last Post: Dec 24, 2012 2:06 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
William Hughes

Posts: 1,818
Registered: 12/7/10
Re: UNCOUNTABILITY
Posted: Dec 22, 2012 9:55 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Dec 22, 7:04 pm, Virgil <vir...@ligriv.com> wrote:
> In article
> <2263ace1-dfa7-466d-8341-c50692402...@v7g2000yqv.googlegroups.com>,
>  William Hughes <wpihug...@gmail.com> wrote:
>

> > Note, that
> > subcountable
> > does not mean countable.

>
> I am not at all sure of what you mean by subcountable.


A set X is subcountable if we can associate a different natural number
with every element x of X, call it f(x) In classical mathematics
subcountable
implies countable because f(X) must be a subset of the natural
numbers.
However, if we take a contructivist viewpoint, then we do not know
that f(X) is a subset (it may not be contructable). So in
constructive
mathematics the fact that X is subcountable, does not mean we can
find a bijection between X and some subset of the naturals, so X might
not be countable. E.g. in constructive mathematics the (constructive)
reals
are subcountable but not countable.

So the fact that a set is uncountable need not mean it is "bigger"
than
the natural numbers.



Date Subject Author
12/19/12
Read Re: UNCOUNTABILITY
george
12/20/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/20/12
Read Re: UNCOUNTABILITY
Barb Knox
12/20/12
Read Re: UNCOUNTABILITY
ross.finlayson@gmail.com
12/20/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/20/12
Read Re: UNCOUNTABILITY
ross.finlayson@gmail.com
12/20/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/21/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/21/12
Read Re: UNCOUNTABILITY
Virgil
12/20/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/20/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/20/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/21/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/21/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/21/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/21/12
Read Re: UNCOUNTABILITY
Virgil
12/21/12
Read Re: UNCOUNTABILITY
William Hughes
12/22/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/22/12
Read Re: UNCOUNTABILITY
William Hughes
12/22/12
Read Re: UNCOUNTABILITY
Virgil
12/22/12
Read Re: UNCOUNTABILITY
William Hughes
12/22/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/23/12
Read Re: UNCOUNTABILITY
Virgil
12/23/12
Read Re: UNCOUNTABILITY
William Hughes
12/24/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/24/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/24/12
Read Re: UNCOUNTABILITY
Virgil
12/23/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/23/12
Read Re: UNCOUNTABILITY
Virgil
12/23/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/23/12
Read Re: UNCOUNTABILITY
William Hughes
12/24/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/24/12
Read Re: UNCOUNTABILITY
Virgil
12/23/12
Read Re: UNCOUNTABILITY
Virgil
12/22/12
Read Re: UNCOUNTABILITY
Virgil
12/21/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/22/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/22/12
Read Re: UNCOUNTABILITY
William Hughes
12/22/12
Read Re: UNCOUNTABILITY
Virgil
12/21/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/21/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/21/12
Read Re: UNCOUNTABILITY
Virgil
12/22/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/22/12
Read Re: UNCOUNTABILITY
Virgil
12/22/12
Read Re: UNCOUNTABILITY
Zaljohar@gmail.com
12/22/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/22/12
Read Re: COUNTABILITY of a set requires N to surject to it
Virgil
12/22/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/22/12
Read Re: UNCOUNTABILITY
Virgil
12/23/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/23/12
Read Re: UNCOUNTABILITY
Virgil
12/21/12
Read Re: UNCOUNTABILITY
Virgil
12/20/12
Read Re: UNCOUNTABILITY
Virgil
12/20/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/20/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/21/12
Read Re: UNCOUNTABILITY
mueckenh@rz.fh-augsburg.de
12/21/12
Read Re: UNCOUNTABILITY
Virgil
12/21/12
Read Re: UNCOUNTABILITY
Graham Cooper
12/21/12
Read Re: UNCOUNTABILITY
Graham Cooper

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

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.