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Re: Is there way to use something like Assuming with the

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  • Subject: [mg128760] Re: Is there way to use something like Assuming with the
  • From: Bob Hanlon <hanlonr357 at gmail.com>
  • Date: Sat, 24 Nov 2012 02:25:26 -0500 (EST)
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  • References: <20121123082533.A76536891@smc.vnet.net>

"Assuming[assum, expr] evaluates expr with assum appended to
$Assumptions, so that assum is included in the default assumptions
used by functions such as Refine, Simplify, and Integrate."

list = {1, -2, a, 3};

Assuming[a < 0, Simplify[Sign[list]]]

{1, -1, -1, 1}

However, more compactly

Simplify[Sign[list], a < 0]

{1, -1, -1, 1}


Bob Hanlon


On Fri, Nov 23, 2012 at 3:25 AM, Eduardo Mendes <emammendes at hotmail.com> wrote:
> Hello
>
> I was wondering there is something similar to what can be done with Integrate, Reduce and Limit.  Something like
>
> list={1,-2,a,3}
>
> Assuming[a<0,Sign[list]]
>
> Mathematica returns {1,-1,Sign[a],1} and I would like to see something like {1,-1,-1,1}.   Can that be done?
>
> Many thanks
>
> Ed
>
>



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