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. >