Opened 4 years ago

Last modified 4 years ago

## #18902 new defect

# spurious results as inequality solution — at Version 1

Reported by: | rws | Owned by: | |
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Priority: | major | Milestone: | sage-6.8 |

Component: | symbolics | Keywords: | |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description (last modified by )

From, http://ask.sagemath.org/question/26941/solving-system-of-inequalities-in-one-variable/:

x = var('x') a = var('a') solve([a*x>0,a>0],[x]) [[0 < x, a > 0], [x < 0, -a > 0, a > 0]]

The second solution contradicts one given precondition.

Also, from http://ask.sagemath.org/question/26410/test-if-an-inequality-is-feasible-under-assumptions/

sage: (l1,l2) = var("l1 l2") sage: assume (l1>=0) sage: assume (l2>=0) sage: solve (l1*l2<0, [l1,l2]) [[0 < l2, l1 < 0], [l2 < 0, 0 < l1]]

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