MatLab also have something similar to our UniversalSet http://www.mathworks.in/help/symbolic/mupad_ref/universe.html.
On Saturday, 10 May 2014 23:33:12 UTC+5:30, 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. > > I want to know the views of the community on this matter. > -- 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/18306a59-9051-4b5e-84bf-7866bcdca2f4%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
