Opened 5 years ago

## #21939 new defect

# Solving with respect to a dummy variable behaves wrong

Reported by: | pelegm | Owned by: | |
---|---|---|---|

Priority: | major | Milestone: | sage-7.5 |

Component: | symbolics | Keywords: | solve, days79 |

Cc: | Merged in: | ||

Authors: | Reviewers: | ||

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

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

Solving an equation which only involves `x`

, with respect to `y`

, gives a solution with respect to `x`

:

sage: var('x,y') (x, y) sage: solve(x > 0, y) [[x > 0]]

(Expected answer: for all `y`

...)

It does not change if one adds `y`

to the equation in a dummy way (like `y*0`

).

Similarly, the following code:

solve(1>x*0, y)

returns `[[]]`

, where the expected result should probably be for all `y`

. For the second example `sympy`

returns `True`

.

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