#10682: sum fails with lower bound != 0 or 1 (upgrade maxima to 5.26)
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Reporter: fmaltey
| Owner: burcin
Type: defect
| Status: needs_work
Priority: critical
| Milestone: sage-5.0
Component: symbolics
| Keywords:
Work_issues: several doctests need to be patched due to changes in output
format/term order | Upstream: N/A
Reviewer:
| Author:
Merged:
| Dependencies:
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Comment(by mjo):
For the assumptions, we don't necessarily need maxima to recognize them.
If the user tells us that `x>0`, then we should be able to set `domain:
real` whether or not maxima is going to use that information.
In simplification, I gather that maxima doesn't really know about
real/complex. The docs simply say,
{{{
Option variable: domain
Default value: real
When domain is set to complex, sqrt (x^2) will remain sqrt (x^2)
instead of returning abs(x).
}}}
They used to add,
{{{
The notion of a "domain" of simplification is still in its infancy, and
controls little more than this at the moment.
}}}
I think we should leave the default `complex` to be on the safe side. We
could strictly improve some things by checking the assumptions, though.
There are a few easy cases that we should be able to handle safely:
1. assume(`x`, 'real')
2. assume(`x` > constant)
3. assume(`x` > `y`) (where `y` is known to be real by similar reasoning)
4. et cetera
If all variables in an expression are determined to be real, we can set
`domain: real` before asking maxima to do anything with it.
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/10682#comment:34>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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