Opened 2 years ago

Closed 2 years ago

#30401 closed defect (fixed)

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

Reported by: Travis Scrimshaw Owned by:
Priority: major Milestone: sage-9.2
Component: manifolds Keywords:
Cc: Eric Gourgoulhon, Michael Jung 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 2 years ago by Eric Gourgoulhon

Branch: → public/manifolds/union_subsets_30401
Commit: → bbe5d11bb921f2ff0e2091d95fe304aaea472dee

New commits:

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

comment:2 Changed 2 years ago by Eric Gourgoulhon

Authors: → Eric Gourgoulhon
Status: new → needs_review

comment:3 Changed 2 years ago by Travis Scrimshaw

Reviewers: → Travis Scrimshaw
Status: needs_review → positive_review

Thank you.

comment:4 Changed 2 years ago by Eric Gourgoulhon

Thanks for having reported the bug and performed the review.

comment:5 Changed 2 years ago by Volker Braun

Branch: public/manifolds/union_subsets_30401 → bbe5d11bb921f2ff0e2091d95fe304aaea472dee
Resolution: → fixed
Status: positive_review → closed
Note: See TracTickets for help on using tickets.