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Publié : **mar. août 04, 2015 8:46 am**

Hello!

We are using Giac v1.2.0 compiled from source. We have found some inconsistencies in handling compound inequations. Namely:

Input:

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solve((y)^(2) - 3.5 < 5 < y + 9, y)

Output:

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Inequation inside inequation not implemented (y^2-7/2-y-9)<(5-y-9) Error: Bad Argument Value

However, if we just slightly change the input to:

Input:

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solve((y)^(2) - 3.5 < y < y + 9, y)

we get much more friendly output:

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list[((y>((-sqrt(15)+1)/2)) and (y<((sqrt(15)+1)/2)))]

which is the same as when inputting

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solve(list[(y)^(2) - 3.5 < y, y < y + 9], y)

Currently, we have a workaround for this to automatically detect compound inequalities in our code and make sure list of inequations form is used when invoking GIAC.

Publié : **mar. août 04, 2015 8:26 pm**

The parser does not accept double inequations (otherwise I would get reduce/reduce conflicts with bison), there is only one exception, if the middle term is a symbol (like y in your 2nd example).

Publié : **mer. août 05, 2015 9:48 am**

Thank you for explanation!

Le forum de XCAS

Compound inequation inconsistency

Compound inequation inconsistency

Re: Compound inequation inconsistency

Re: Compound inequation inconsistency