Opened 8 years ago
Last modified 6 years ago
#14229 needs_work enhancement
Remove vacuous solutions from solve — at Version 2
Reported by: | ppurka | Owned by: | burcin |
---|---|---|---|
Priority: | major | Milestone: | sage-6.4 |
Component: | symbolics | Keywords: | |
Cc: | kcrisman, jondo | Merged in: | |
Authors: | Reviewers: | ||
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description (last modified by )
Sometimes solve and its variants tend to report vacuous solutions. A recent one from ask.sagemath is the following:
sage: x,y = var('x,y') sage: solve([x^2*y^2 <= x^2*y, x^2*y^2 > x^2*y],[x,y]) [[x == 0, 1 < y, 0 != 0], [x == 0, y < 0, 0 != 0]]
Shouldn't we remove these meaningless solutions? The attached patch contains a potential solution. If it seems reasonable, then similar changes could be introduced in solve_ineq
.
The output of the above command after this patch is as expected:
sage: x,y = var('x,y') sage: solve([x^2*y^2 <= x^2*y, x^2*y^2 > x^2*y],[x,y]) []
Change History (3)
Changed 8 years ago by
comment:1 Changed 8 years ago by
- Description modified (diff)
comment:2 Changed 8 years ago by
- Description modified (diff)
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