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Re: Re: confused about asserting variable is element of

• To: mathgroup at smc.vnet.net
• Subject: [mg103170] Re: [mg103141] Re: confused about asserting variable is element of
• From: Leonid Shifrin <lshifr at gmail.com>
• Date: Thu, 10 Sep 2009 07:16:14 -0400 (EDT)
• References: <200909070636.CAA04019@smc.vnet.net> <h859vn$q48$1@smc.vnet.net>

I don't find anything wrong here:

In[1]:= Simplify[Re[I + 1], Assumptions -> Element[I, Reals]]

During evaluation of In[1]:= Simplify::fas: Warning: One or more assumptions
evaluated to False. >>

Out[1]= 1


On Wed, Sep 9, 2009 at 12:42 PM, AES <siegman at stanford.edu> wrote:

> In article <h859vn$q48$1 at smc.vnet.net>,
>  Leonid Shifrin <lshifr at gmail.com> wrote:
>
> > When you enter Element[a, Reals], this by itself does nothing. It does
> not,
> > in particular, change  any global property of symbol <a>.
> >
> > However, this expression can be used in
> > commands like Simplify, FullSimplify, etc., to give them the information
> > that <a> should be considered real (in that particular computation):
>
> So, could one ever write Assumptions -> Element[I, Reals]  in any of
> those commands?
>
>

• References:
  • confused about asserting variable is element of Reals
    • From: dushan <dushanm@spinn.net>