Re: Re: confused about asserting variable is element of
- To: mathgroup at smc.vnet.net
- Subject: [mg103180] Re: [mg103141] Re: confused about asserting variable is element of
- From: Daniel Lichtblau <danl at wolfram.com>
- Date: Thu, 10 Sep 2009 07:18:08 -0400 (EDT)
- References: <200909070636.CAA04019@smc.vnet.net> <h859vn$q48$1@smc.vnet.net> <200909090842.EAA05849@smc.vnet.net>
AES wrote: > In article <h859vn$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? Of course one can. Look, I'll do it below. In[13]:= Simplify[Re[I*x], Assumptions->Element[I, Reals]] Simplify::fas: Warning: One or more assumptions evaluated to False. Out[13]= 0 Some people refer to this as GIGO. I am partial to the phrase "You get what you get". Daniel Lichtblau Wolfram Research
- References:
- confused about asserting variable is element of Reals
- From: dushan <dushanm@spinn.net>
- Re: confused about asserting variable is element of Reals
- From: AES <siegman@stanford.edu>
- confused about asserting variable is element of Reals