#16676: Cardinality of infinite sets loops forever
--------------------------------------+------------------------
Reporter: defeo | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.3
Component: combinatorics | Resolution:
Keywords: sets infinite_loop | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
--------------------------------------+------------------------
Comment (by kcrisman):
> > > This is a different problem and an easy fix, though, as long as we
agree that `False` means "I don't know".
> >
> > I do not agree.
>
> Me neither. So I guess someone must step up and add three-way logic to
the Set API. A grep for `Unknown` in Sage src shows three-way logic is
used almost nowhere inside Sage, and certainly not in sets.
Sage (for now) says `True` only if we know for sure it is true, otherwise
`False`. One would have to have a discussion on sage-devel otherwise -
and of course that is a long thing to implement. The problem is, among
others, that lots of symbolic expressions might or might not be zero, and
the question is how much computation to invest in trying to discern
this...
--
Ticket URL: <http://trac.sagemath.org/ticket/16676#comment:5>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
