Re: InequalitySolve
- To: mathgroup at smc.vnet.net
- Subject: [mg37790] Re: [mg37767] InequalitySolve
- From: Gianluca Gorni <gorni at dimi.uniud.it>
- Date: Wed, 13 Nov 2002 01:10:59 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
While I was playing around with the definition of continuity,
I stumbled upon a wrong output from InequalitySove under Mathematica
4.1 (for MacOS classic).
Here is the code:
Needs["Algebra`InequalitySolve`"];
f[x_] := (x^2 - 1)/(x^2 + 1);
x0 = 2;
p = And[0 < e < 8/5, 0 < d ¾ 2 - Sqrt[(8 - 5e)/(2 + 5e)]];
q = Implies[x0 - d < x < x0 + d, f[x0] - e < f[x] < f[x0] + e];
mySistem = Implies[p, q];
myValues = {e -> Sqrt[11]/10, x -> 0, d -> 3};
myValues are a solution of mySistem:
In: mySistem /. myValues
Out: True
However, InequalitySolve does not find that solution:
In: InequalitySolve[mySistem, {e, d, x}] /. myValues
Out: False
CylindricalAlgebraicDecomposition gets it wrong too,
but at least it displays some error messages before the
output.
This particular system of inequalities seems to run fine under
Mathematica version 4.2. Let's hope that the bug is fixed.
Gianluca Gorni
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