While working on http://trac.sagemath.org/sage_trac/ticket/14291, it
came to my attention that one can now have permutation groups acting
on quite arbitrary domains (the only requirement for the domain elements
seems to be them being hashable).
This leads to the following kind of confusing situations:
suppose our permutation group G acts on, say, (1,2,3,4,(1,2),(2,3)).
Then things like "the orbit (1,2) under G" can be interpreted in two
different incompatible ways:
* the images under G of the pair of domain elements 1 and 2.
* the images under G of of the domain element (1,2).
I can see two ways to remedy this:
1) a framework with parents, etc
2) "boxing" the most "primitive" elements of the domain, i.e.
as in our example, using ((1),(2),(3),(4),(1,2),(2,3)) instead of
(1,2,3,4,(1,2),(2,3)); then certainly ((1),(2)) and (1,2) are
different things, problem solved.
(and certainly you can tell me that actually it's OK as it is... :))
IMHO, 2) is relatively easy to put into place, and 1) is tricky and quite a bit
of
work.
Dima
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to sage-devel+unsubscr...@googlegroups.com.
To post to this group, send email to sage-devel@googlegroups.com.
Visit this group at http://groups.google.com/group/sage-devel?hl=en.
For more options, visit https://groups.google.com/groups/opt_out.
