Improvement in solveset for inequalities

[maurogaravello]

References to other Issues or PRs

Fixes #19977

Brief description of what is fixed or changed

The inequality atan(log(x)) > 0 in the domain Interval.open(0, oo) is not properly solved by solveset, which
returns ConditionSet instead of Interval.Open(1, oo). This is due mainly to line 643 (and line 666) of inequalities.py.
Indeed valid(start) in such situation returns NotImplementedError and so the execution of solve_univariate_inequality stops.
In such case start is equal to 0, which is outside the domain; so it is useless to add start to sol_sets.

Incidentally this change produces some failures in test_inequalities.py, due to periodicity issue.
Indeed in such cases, solve_univariate_inequality checks the periodicity (which is pi or 2pi) and at lines 513-514 defines a new domain accordingly. The new domain is left closed and right open.
So if one respects this choice, then we need to eliminate the rightmost point in the solution.

Other comments

Release Notes

• solvers
  • improved functionality for solveset in case of inequalities

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• solvers
  • improved functionality for solveset in case of inequalities (#19978 by @maurogaravello)

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#### References to other Issues or PRs

Fixes #19977 
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#### Brief description of what is fixed or changed

The inequality `atan(log(x)) > 0` in the domain `Interval.open(0, oo)` is not properly solved by `solveset`, which
returns `ConditionSet` instead of `Interval.Open(1, oo)`. This is due mainly to line 643 (and line 666) of `inequalities.py`.
Indeed `valid(start)` in such situation returns `NotImplementedError` and so the execution of `solve_univariate_inequality` stops.
In such case `start` is equal to `0`, which is outside the domain; so it is useless to add `start` to `sol_sets`.

Incidentally this change produces some failures in `test_inequalities.py`, due to periodicity issue.
Indeed in such cases, `solve_univariate_inequality` checks the periodicity (which is `pi` or `2pi`) and at lines 513-514 defines a new domain accordingly. The new domain is left closed and right open.
So if one respects this choice, then we need to eliminate the rightmost point in the solution.

#### Other comments


#### Release Notes

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https://github.com/sympy/sympy/wiki/Writing-Release-Notes for more information
on how to write release notes. The bot will check your release notes
automatically to see if they are formatted correctly. -->

<!-- BEGIN RELEASE NOTES -->
- solvers
  - improved functionality for solveset in case of inequalities


<!-- END RELEASE NOTES -->

Update

The release notes on the wiki have been updated.

[codecov]

Codecov Report

Merging #19978 into master will decrease coverage by 16.261%.
The diff coverage is 100.000%.

@@              Coverage Diff               @@
##            master    #19978        +/-   ##
==============================================
- Coverage   75.832%   59.570%   -16.262%     
==============================================
  Files          669       669                
  Lines       173451    173476        +25     
  Branches     40903     40911         +8     
==============================================
- Hits        131532    103341     -28191     
- Misses       36196     64280     +28084     
- Partials      5723      5855       +132     

[oscarbenjamin]

Looks good. Thanks!