Problem with Simplify with Assumptions

*To*: mathgroup at smc.vnet.net*Subject*: [mg131388] Problem with Simplify with Assumptions*From*: "Dave Snead" <dsnead6 at charter.net>*Date*: Wed, 3 Jul 2013 04:55:45 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net

Hi, I'm trying to simplify some expression with assumptions. When I input Simplify[x^2 + y^2 + z^2, p^2 == x^2 + y^2 + z^2] the output is x^2 + y^2 + z^2 (which fails to simplify). But if I change the symbol names from x,y,z to a,b,c, i.e., Simplify[a^2 + b^2 + c^2, p^2 == a^2 + b^2 + c^2] the output is p^2 (it simplifies!). How do I get Simplify to always implement this latter behavior irrespective of the symbol names? Thanks in advance, Dave Snead