Mathematics in Python are not correct

Lou Pecora pecora at anvil.nrl.navy.mil
Fri May 9 11:23:42 EDT 2008


In article <mailman.825.1210293599.12834.python-list at python.org>,
 "Terry Reedy" <tjreedy at udel.edu> wrote:

> "Luis Zarrabeitia" <kyrie at uh.cu> wrote in message 
> news:200805081914.06459.kyrie at uh.cu...
> | Btw, there seems to be a math problem in python with exponentiation...
> | >>> 0**0
> | 1
> | That 0^0 should be a nan or exception, I guess, but not 1.
> 
> a**b is 1 multiplied by a, b times.  1 multiplied by 0 no times is 1.
> But there are unenlighted people who agree with you ;-)
> Wikipedia has a discussion of this.
> 
> tjr

I like that argument better.  But...

I've also heard the very similar a**b is a multiplied by a b-1 times.  
That gives 0**0=0*(1/0).  Uh, Oh!  If you want consistency with the 
treatment of exponents that might cause problems.  Tough situation when 
you have a "discontinuity" at 0 for x^x.

-- 
-- Lou Pecora



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