Opened 13 years ago
Closed 12 years ago
#1646 closed defect (duplicate)
'matrix in group' test doesn't work
Reported by: | schilly | Owned by: | joyner |
---|---|---|---|
Priority: | critical | Milestone: | sage-duplicate/invalid/wontfix |
Component: | group theory | Keywords: | |
Cc: | Merged in: | ||
Authors: | Reviewers: | ||
Report Upstream: | Work issues: | ||
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
The code
G = SL(2,ZZ) M = matrix([[1,0],[0,1]]) M in G
runs possibly forever inside GAP. same for
M = matrix(ZZ,[[1,0],[0,1]])
Change History (7)
comment:1 Changed 13 years ago by
- Milestone set to sage-2.9.2
comment:2 Changed 13 years ago by
- Priority changed from major to critical
comment:3 Changed 13 years ago by
comment:4 Changed 13 years ago by
- Component changed from linear algebra to group_theory
- Owner changed from was to joyner
I've reported this to GAP support.
comment:5 Changed 13 years ago by
from Laurent Bartholdi <laurent.bartholdi@…> to David Joyner <wdjoyner@…>, cc GAP Support <support@…>, date Jan 24, 2008 5:36 PM subject Re: [GAP Support] membership in SL(2,Z) mailed-by gmail.com hide details 5:36 PM (27 minutes ago) Reply It's not intentional, and should be fixed. Here's a quick solution:
InstallMethod?(\in,[IsMatrix?,IsSpecialLinearGroup?],
function(g,G)
return Length(g)=Length(One(G)) and
ForAll?(g,row->Length(row)=Length(One(g)) and IsOne?(DeterminantMat?(g));
end);
needless to say, there must be lots of other missing methods; e.g. for general, symplectic etc. linear groups.
- Hide quoted text -
On Jan 24, 2008 9:16 PM, David Joyner <wdjoyner@…> wrote:
Hi:
I wonder if the behavior of
gap> G := SL(2,Integers); SL(2,Integers) gap> g := 1,0],[0,1?; [ [ 1, 0 ], [ 0, 1 ] ] gap> g in G; user interrupt at ....
is intentional: it just hangs, as far as I can tell. Unless I'm doing something wrong, I wonder if an error message should be returned? Perhaps "method not implemented" or something?
- David Joyner
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comment:6 Changed 12 years ago by
This is a duplicate of #1834, which has been fixed and merged in 3.1.2.alpha4.
comment:7 Changed 12 years ago by
- Milestone changed from sage-3.1.2 to sage-duplicate/invalid
- Resolution set to duplicate
- Status changed from new to closed
Alex,
Thanks for finding the dupe. Closed as duplicate.
Cheers,
Michael
This is due to GAP. Unless we get GAP to fix this, then the best solution would be for SL to override the contains method.