Opened 3 years ago

Last modified 3 years ago

#21228 new enhancement

Polyhedron.restricted_automorphism_group(): allow returning an actual affine group

Reported by: mkoeppe Owned by:
Priority: major Milestone: sage-wishlist
Component: geometry Keywords:
Cc: jdemeyer, vbraun Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Description

This is a follow-up on #20259, which added the output="matrix" argument to restricted_automorphism_group. It returns a MatrixGroup.

In this ticket, I propose to add output="affine" to return an AffineGroup.

Change History (5)

comment:1 in reply to: ↑ description Changed 3 years ago by jdemeyer

Replying to mkoeppe:

In this ticket, I propose to add output="affine" to return an AffineGroup.

I wonder why I didn't do that in #20259. Either I didn't know about AffineGroup or it was lacking in functionality.

comment:2 follow-up: Changed 3 years ago by jdemeyer

Answering my own question: it seems that an AffineGroup always refers to the group of all affine transformations, not a subgroup.

So, as far as I can tell, the object you want to return doesn't exist in Sage (and it would be non-trivial work to implement it).

comment:3 in reply to: ↑ 2 Changed 3 years ago by mkoeppe

  • Milestone changed from sage-7.4 to sage-wishlist

Replying to jdemeyer:

Answering my own question: it seems that an AffineGroup always refers to the group of all affine transformations, not a subgroup.

So, as far as I can tell, the object you want to return doesn't exist in Sage (and it would be non-trivial work to implement it).

Thanks! I was already wondering why there was no method to make a subgroup (though methods subsemigroup and submonoid exist).

comment:4 Changed 3 years ago by jdemeyer

Shouldn't we just close this ticket for now?

comment:5 Changed 3 years ago by mkoeppe

I've instead created a ticket for subgroups of AffineGroup - #21275

Note: See TracTickets for help on using tickets.