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: Formal proof of the ambiguity of 0^0
Replies: 163   Last Post: Nov 13, 2013 10:45 AM

Advanced Search

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

Posts: 2,613
Registered: 7/9/08
Re: Formal proof of the ambiguity of 0^0
Posted: Oct 20, 2013 11:09 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

MY SUMMARY

What's wrong with defining 0^0=1? As anyone familiar with the Binomial Theorem knows, it is a very convenient notion and avoids having to consider as a separate case expressions such as (2+0)^0 (even if it would be trivial to do so). (See http://en.wikipedia.org/wiki/Binomial_theorem) It is even possible, by various means (e.g. my Theorem 1 here), to formally construct or prove the existence of a binary function ^ on N such that

1. x^0 = 1
2. x^(y+1) = x^y * x

and to derive from this definition the usual Laws of Exponents:

1. x^y * x^z = x^(y+z)
2. (x^y)^z = x^(y*z)
3. (x*y)^z = x^z * y^z

where 0^0 = 1.

The trouble is, convenience aside, 0^0 = 0 also has these pleasing properties. It is also possible to formally construct or prove the existence of another binary function ^ on N such that

1. 0^0 = 0
2. x^0 = 1 for x=/=0
3. x^(y+1) = x^y * x

and to derive exactly the same Laws of Exponents as above.

In the absence of any logically compelling reasons (if mere convenience is not enough for the skeptics), 0^0 must be considered ambiguous (undefined or indeterminate). But, as I have formally proven here, there are infinitely many binary functions ^ on N that share the following characteristics:

1. x^0 = 1 for x=/=0
2. x^(y+1) = x^y * x

And that, from these properties, it is possible to derive only slight modified versions of the above Laws of Exponents:

1. x^y * x^z = x^(y+z) for x=/=0
2. (x^y)^z = x^(y*z) for x=/=0
3. (x*y)^z = x^z * y^z for x=/=0 and y=/=0

(As one reader pointer out here, it is possible to tighten these stipulations so that other cases are covered, e.g. 0^2 * 0^3 = 0^(2+3).)

Clearly, it bothers some readers here that there is not just one, but infinitely many functions on N that fit all our requirements for exponentiation (i.e. for repeated multiplication). As I have shown here, however, this notion can be put on a rigorously sound mathematical footing using only the axioms and rules of ordinary logic and set theory. I, therefore, feel justified in defining exponentiation on N as a binary function ^ such that

1. x^0 = 1 for x=/=0
2. x^(y+1) = x^y * x

where 0^0 is an unspecified natural number.

Dan
Download my DC Proof 2.0 software at http://www.dcproof.com
Visit my new math blog at http://www.dcproof.wordpress.com





Date Subject Author
10/16/13
Read Formal proof of the ambiguity of 0^0
Dan Christensen
10/16/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
ross.finlayson@gmail.com
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
fom
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Ben Bacarisse
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/17/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/23/13
Read Re: Formal proof of the ambiguity of 0^0
Shmuel (Seymour J.) Metz
10/25/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/29/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Richard Tobin
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
fom
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
David Bernier
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
David Bernier
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/31/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/30/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/30/13
Read what is 0^0 in complex. quaternion & octonion units, again
Brian Q. Hutchings
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
fom
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
fom
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/18/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Michael F. Stemper
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/23/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
fom
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
JT
10/21/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Peter Percival
10/20/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/23/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
10/23/13
Read Re: Formal proof of the ambiguity of 0^0
fom
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
fom
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read base-one accounting (just day, Duh, thank you
Brian Q. Hutchings
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Brian Q. Hutchings
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
ross.finlayson@gmail.com
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
ross.finlayson@gmail.com
11/3/13
Read 0^0
Brian Q. Hutchings
11/1/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/12/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/12/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/12/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/12/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/13/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/13/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Virgil
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Paul
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
Bart Goddard
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Ki Song
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Virgil
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Michael F. Stemper
11/2/13
Read Re: Formal proof of the ambiguity of 0^0
Virgil
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
Michael F. Stemper
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
Robin Chapman
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
fom
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
Jussi Piitulainen
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
fom
11/4/13
Read Re: Formal proof of the ambiguity of 0^0
Jussi Piitulainen
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
JT
11/3/13
Read Re: Formal proof of the ambiguity of 0^0
JT
11/12/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen
11/13/13
Read Re: Formal proof of the ambiguity of 0^0
Dan Christensen

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.