FullSimplify issue

*To*: mathgroup at smc.vnet.net*Subject*: [mg124150] FullSimplify issue*From*: Tiago <aswedieinparadise at gmail.com>*Date*: Wed, 11 Jan 2012 04:21:52 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Hello, I want to simplify an expression. FullSimplify does it only if I include an assumption that has nothing to do with the expression that I want to simplify. Here is the code: ListOfAssumptions = { b[3] c[1] - b[1] c[3] == 2 Area, p[1] + q[1] + 1 == 0, p[2] + q[2] + 1 == 0, p[3] + q[3] + 1 == 0, b[1] + b[2] + b[3] == 0, c[1] + c[2] + c[3] == 0, (b[1] b[2] + c[1] c[2])/s[1]^2 == p[1], (b[2] b[3] + c[2] c[3])/s[2]^2 == p[2], (b[3] b[1] + c[3] c[1])/s[3]^2 == p[3], (b[1] b[3] + c[1] c[3])/s[1]^2 == q[1], (b[2] b[1] + c[2] c[1])/s[2]^2 == q[2], (b[3] b[2] + c[3] c[2])/s[3]^2 == q[3], (-s[1]^2 - s[2]^2 + s[3]^2)/(2 s[1]^2) == p[1] }; FullSimplify[(15 (-2 q[3] s[1]^4 + 4 (1 + q[3]) s[1]^2 s[2]^2 - 2 (2 + q[3]) s[2]^4 + (s[1]^2 + 3 s[2]^2) s[3]^2 - s[3]^4))/(4 (b[3] c[2] - b[2] c[3])^2), Assumptions -> ListOfAssumptions] The result is 30 (1 + q[3]) If I remove from the assumptions list the first assumption (b[3] c[1] - b[1] c[3] == 2 Area) the result becomes a very large expression. What should I do in order to not use the assumption b[3] c[1] - b[1] c[3] == 2 Area ? (This is important because this is a minimal example from a big set of expressions). Thanks, Carlos Fernandes