Re: minor bug
- To: mathgroup at smc.vnet.net
- Subject: [mg41245] Re: minor bug
- From: Adam Strzebonski <adams at wolfram.com>
- Date: Fri, 9 May 2003 03:23:33 -0400 (EDT)
- References: <E9E53838-815A-11D7-A88C-00039311C1CC@mimuw.edu.pl>
- Sender: owner-wri-mathgroup at wolfram.com
It will be fixed in the upcoming Mathematica version.
In[1]:= Simplify[Element[a/b, Rationals], Element[a|b, Rationals]]
a
Out[1]= - \[Element] Rationals
b
In[2]:= Simplify[Element[a/b, Rationals], Element[a|b, Rationals] && b!=0]
Out[2]= True
Best Regards,
Adam Strzebonski
Wolfram Research
Andrzej Kozlowski wrote:
> While teaching an introductory analysis class I noticed a (minor) bug in
> Simplify:
>
>
> Simplify[a/b ? Reals, (a | b) ? Reals]
>
> a/b ? Reals
>
> This is correct. We do not know if b is non-zero.
>
>
> Simplify[a/b ? Reals, (a | b) ? Reals && b != 0]
>
> True
>
> Quite right.
>
>
> Simplify[a/b ? Rationals, (a | b) ? Rationals]
>
> True
>
> ?
>
> Andrzej Kozlowski
> Yokohama, Japan
> http://www.mimuw.edu.pl/~akoz/
> http://platon.c.u-tokyo.ac.jp/andrzej/
>