id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
13695,Subsets(1)[x] behaves strangely for x in SR,ppurka,sage-combinat,"This bug is from the [https://spreadsheets.google.com/pub?key=pCwvGVwSMxTzT6E2xNdo5fA sage notebook bug report page].
{{{
A = Subsets(1);
k=var('k')
sum((-1)^(A[k].cardinality()),k,0,A.cardinality()-1)
Sage gives me 2 as an answer, while it should be 0.
}}}
The problem seems to be in `sage.combinat.subset.Subsets_s.unrank` which does not check whether the arguments it receives are integers or not. So, doing something like the title gives the empty set and so we get 2 as the answer above.
{{{
sage: Subsets(1)[x]
{}
}}}",defect,closed,major,sage-duplicate/invalid/wontfix,combinatorics,wontfix,,,,,Vincent Delecroix,N/A,,,,,