Opened 8 years ago
Closed 6 years ago
#14684 closed defect (fixed)
Convert between free group elements considering generator names.
Reported by:  mmarco  Owned by:  mmarco 

Priority:  major  Milestone:  sage6.4 
Component:  group theory  Keywords:  free groups 
Cc:  vbraun, sydahmad, vdelecroix, jhpalmieri, tjolivet, rbeezer, dimpase, dshurbert  Merged in:  
Authors:  Miguel Marco  Reviewers:  Vincent Delecroix 
Report Upstream:  N/A  Work issues:  
Branch:  4a479ed (Commits)  Commit:  4a479edb0db34d4d9d956dd2a1c306d93a00c7e1 
Dependencies:  Stopgaps: 
Description
Right now, when we try to convert elements between free groups, they just get converted to the Tietze list, forgeting about the names of the generators. This can cause strange behaviour like:
sage: F.<a,b>=FreeGroup() sage: G.<b,a>=FreeGroup() sage: F(a) b
This patch solves this, looking for generators with matching names.
Attachments (1)
Change History (21)
Changed 8 years ago by
comment:1 Changed 8 years ago by
 Status changed from new to needs_review
comment:2 Changed 8 years ago by
 Cc vbraun sydahmad vdelecroix jhpalmieri tjolivet rbeezer dimpase dshurbert added
comment:3 Changed 8 years ago by
 Owner changed from joyner to mmarco
comment:4 Changed 8 years ago by
 Priority changed from minor to major
comment:5 Changed 7 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:6 Changed 7 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:7 Changed 7 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:8 Changed 6 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:9 Changed 6 years ago by
 Branch set to public/14684
 Commit set to b2d253d9feeab81f73eaab3e484c6acbe7d34144
 Status changed from needs_review to needs_info
comment:10 Changed 6 years ago by
It is an error. It should be _free_group (finitely presented groups have that attribute, that contains the free group after which they are defined).
Apparently it works even without that because the element_class init first tries to get the Tietze list anyways.
comment:11 Changed 6 years ago by
So please, fix that!
comment:12 Changed 6 years ago by
 Status changed from needs_info to needs_work
comment:13 Changed 6 years ago by
 Branch changed from public/14684 to u/mmarco/ticket/14684
 Created changed from 06/04/13 01:11:06 to 06/04/13 01:11:06
 Modified changed from 08/25/14 14:44:52 to 08/25/14 14:44:52
comment:15 Changed 6 years ago by
 Branch changed from public/14684 to u/mmarco/ticket/14684
 Commit changed from b2d253d9feeab81f73eaab3e484c6acbe7d34144 to 4a479edb0db34d4d9d956dd2a1c306d93a00c7e1
 Status changed from needs_work to needs_review
Thanks. If it is, your commit should appear on this page... and it does not. I only see your commit at u/mmarco/ticket/14684
(public/14684
is one commit back). I switch back to the name of the branch that you used. If you want to commit to a specific branch use git push trac HEAD:public/14684
.
Vincent
New commits:
4a479ed  Remved unnecessary check for _freegroup_

comment:16 Changed 6 years ago by
 Reviewers set to Vincent Delecroix
 Status changed from needs_review to positive_review
Perfect!
Vincent
comment:17 Changed 6 years ago by
 Status changed from positive_review to needs_work
Author name should be real name, not trac username
comment:19 Changed 6 years ago by
 Status changed from needs_work to positive_review
comment:20 Changed 6 years ago by
 Branch changed from u/mmarco/ticket/14684 to 4a479edb0db34d4d9d956dd2a1c306d93a00c7e1
 Resolution set to fixed
 Status changed from positive_review to closed
Hello,
I created a branch from the ticket with
sage dev
. The review can starts from there.What's the point of the following code in
_element_constructor_
?As far as I looked, there is no object in Sage with a
_freegroup_
attribute.Vincent
New commits:
Trac #14684: make conversion between free groups aware of generator names