Automatic simplification fails with singletons in special cases

[TimBergner]

The automatic simplification seems to fail with singletons if it closes exactly one gap. In this case the singleton is only added to the left open interval on the right of the sigleton.
Examples:

P.open(1, 2) | P.open(2, 3) | P.singleton(2)
>>> (1,2) | [2,3)
P.open(1, 3) & ~P.singleton(2) | P.singleton(2)
>>> (1,2) | [2,3)

If the result is stored in a Variable x, further calculations might be faulty:

P.open(1, 3) in x
>>> False

[TimBergner]

Of course one of the most important information was only implicit in the examples: the problem concerns the merge function.

[AlexandreDecan]

Hello,

Thank you for having reported this issue! I'll have a look asap and try to release a hotfix asap as well :-)

[AlexandreDecan]

I found the issue. When intervals are simplified, the underlying atomic intervals are sorted by their lower bound. and an attempt to merge them is made. Since (2, 3) and [2] have the same lower bound, the order in which they are provided defines the order in which they will be considered (and that's why (1, 2) | [2] | (2, 3) works): it tries first to merge (1, 2) and (2, 3) (they can't), then (2, 3) and [2] (which results in [2, 3)).

I'll confirm this asap, fix it, and release a hotfix.

[AlexandreDecan]

Fixed in 39e2564

Fix will be released in a few minutes as part of version 2.1.2.