Re: Consrtaining Variables
- To: mathgroup at smc.vnet.net
- Subject: [mg26513] Re: [mg26508] Consrtaining Variables
- From: BobHanlon at aol.com
- Date: Sat, 30 Dec 2000 22:13:39 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
With version 4, try using assumptions with Simplify or FullSimplify
Simplify[Abs[a - x], x >= a]
x - a
Factor[Sum[Simplify[Abs[a - x], x >= a], {x, a, 10}]]
(1/2)*(a - 11)*(a - 10)
Sum[Simplify[Abs[a - x], {x >= a, a >= 5}], {x, 0, 10}]
6*a + Abs[a - 10] + Abs[a - 9] + Abs[a - 8] + Abs[a - 7] +
Abs[a - 6] - 15
Bob Hanlon
In a message dated 12/30/00 2:20:27 AM, frumple*NOSPAM* at home.com writes:
>I am working on a package where I need to constrain the domain of some
>
>variables to the non-negative integers. In particular I would like to be
>
>able for Mathematica to recognize that Abs[a-x] = x-a when x>=a where
>the Abs term is in both the limits and kernal of a Sum.
>