Opened 10 months ago

Closed 9 months ago

#30401 closed defect (fixed)

Unions of subsets of a fixed open set X are not known to be subsets of X

Reported by: tscrim Owned by:
Priority: major Milestone: sage-9.2
Component: manifolds Keywords:
Cc: egourgoulhon, gh-mjungmath Merged in:
Authors: Eric Gourgoulhon Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: bbe5d11 (Commits, GitHub, GitLab) Commit: bbe5d11bb921f2ff0e2091d95fe304aaea472dee
Dependencies: Stopgaps:

Status badges

Description

See the following: 

sage: T = Manifold(2, 'T', start_index=1)
sage: U0 = T.open_subset("U0", latex_name="U_0")
sage: Uh = T.open_subset("Uh", latex_name="U_h")
sage: T.declare_union(U0, Uh)
sage: I0h = U0.intersection(Uh, name="I0h", latex_name="I_{0h}")
sage: X1 = I0h.open_subset('X1', "X_1")
sage: X2 = I0h.open_subset('X2', "X_2")
sage: X3 = I0h.open_subset('X3', "X_3")
sage: X1.union(X2).is_subset(I0h)
False

This means I cannot declare I0h as the union of 3 subsets.

Change History (5)

comment:1 Changed 10 months ago by egourgoulhon

  • Branch set to public/manifolds/union_subsets_30401
  • Commit set to bbe5d11bb921f2ff0e2091d95fe304aaea472dee

New commits:

​bbe5d11Fix bug in union of manifold subsets (Trac #30401)

comment:2 Changed 10 months ago by egourgoulhon

  • Authors set to Eric Gourgoulhon
  • Status changed from new to needs_review

comment:3 Changed 10 months ago by tscrim

  • Reviewers set to Travis Scrimshaw
  • Status changed from needs_review to positive_review

Thank you.

comment:4 Changed 10 months ago by egourgoulhon

Thanks for having reported the bug and performed the review.

comment:5 Changed 9 months ago by vbraun

  • Branch changed from public/manifolds/union_subsets_30401 to bbe5d11bb921f2ff0e2091d95fe304aaea472dee
  • Resolution set to fixed
  • Status changed from positive_review to closed
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