On Sat, May 10, 2014 at 11:03:12AM -0700, Harsh Gupta wrote: > This comes from the discussions on this PR > https://github.com/sympy/sympy/pull/7462#issuecomment-42111992 > We have a class called UniversalSet which is supposed to be *set* which > contains all the sets which we can define in Sympy. The problem is that we > really don't "know" what our defined Universal Set is. It has been > proposed by Sergey that we wipe out the Universal Set class. We can > explicitly provide the the known defined universal set when situation asks > for it, that set can be complex, real or real*real or anything. I'm +1 to > the proposal. I guess this goes with "Explicit is better than Implicit" > from the Zen of Python. At places we are implicitly assuming UniversalSet > to Interval(-oo, oo) which is clearly wrong. Then we cannot define > operations like PowerSet and cardinality on such sets. We can avoid the > problem by leaving PowerSet or cardinality undefined for UniversalSet, but > not having an UniversalSet will be a better way to avoid unknown > inconsistencies.
btw, some statistics: $ fgrep -R UniversalSet sympy/|wc -l 22 $ fgrep -R UniversalSet sympy/ 2>/dev/null|grep -v 'core/sets.py'|grep -v 'core/tests/test_sets.py'|wc -l 8 -- You received this message because you are subscribed to the Google Groups "sympy" 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/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/20140510183503.GB18695%40debian. For more options, visit https://groups.google.com/d/optout.
