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CLP(*) stuff in CAS systems

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burs...@gmail.com

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Nov 26, 2016, 8:18:40 AM11/26/16
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CAS = computer algebra system,
they have constraint stores:

sage: x, y, z = var('x y z')
sage: assume(x, 'integer')
sage: assume(y > 0)
sage: assume(y**2 + z**2 == 1)
sage: assume(x < 0)
sage: assumptions()
[x is integer, y > 0, y^2 + z^2 == 1, x < 0]

Even a variable projection API:

sage: assumptions(x)
[x is integer, x < 0]
sage: assumptions(x, y)
[x is integer, x < 0, y > 0, y^2 + z^2 == 1]
sage: assumptions(z)
[y^2 + z^2 == 1]

http://doc.sagemath.org/html/en/reference/calculus/sage/symbolic/assumptions.html
Also in Python sympy and elsewhere seen.

Currently trying some Prolog OO
to bootstrap a simple Prolog based CAS:
https://plus.google.com/+JekejekeCh/posts/L9ob4Qu2ScW

After datatypes integer, rational,
will try a datatypes symbolic, and
do something with attribute variables.

burs...@gmail.com

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Nov 26, 2016, 8:20:55 AM11/26/16
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Am Samstag, 26. November 2016 14:18:40 UTC+1 schrieb burs...@gmail.com:
> Even a variable projection API:
>
> sage: assumptions(x)
> [x is integer, x < 0]
> sage: assumptions(x, y)
> [x is integer, x < 0, y > 0, y^2 + z^2 == 1]
> sage: assumptions(z)
> [y^2 + z^2 == 1]

Without transitve closure it seems, expected result:

> sage: assumptions(z)
> [y > 0, y^2 + z^2 == 1]

burs...@gmail.com

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Nov 29, 2016, 7:43:54 PM11/29/16
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SageMath -- to compete with Mathematica -- via Google Cloud
https://www.youtube.com/watch?v=AEKOjac9obk
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