There is a serious project that could be done for Maxima that would allow
it to deal with a collection of geometric (in)equalities in n dimensions,
determining regions in which inequalities hold. There are many of the
tools available, but I think they are not all put together e.g. as
cylindrical algebraic decomposition.
the checking of category or type facts in a database via featurep and
declare and assume
is another can of worms, and I'm not aware of any clean approach that
would (for example)
be efficient or even guaranteed to terminate.
Barton's proposal seems to require some loop-avoidance fiddling, I think.
RJF
On 12/22/2012 11:05 AM, Barton Willis wrote:
> Consider:
>
> (%i1) assume(equal(a,b),equal(b,c));
> (%o1) [equal(a,b),equal(b,c)]
>
> (%i2) declare(a,noninteger);
> (%o2) done
>
> The function check-noninteger-facts (defined in compar.lisp) isn't
> able to determine that c is an integer:
>
> (%i3) map(lambda([s], featurep(s,noninteger)),[a,b,c]);
> (%o3) [true,true,false]
>
> Maybe somebody would like to figure out how to make
> assume(equal(symbol1, symbol2)) examine symbol1
> for declared properties and automaticallydeclare symbol2 to have the
> sameproperties?
>
>
> --Barton
>
>
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