I think its unambiguous to define the orbit of x recursively as 1. use the action on domain elements if x is a domain element 2. otherwise, assume that the x is a list/set/... of domain elements
On Thursday, March 21, 2013 3:10:38 PM UTC+1, Dima Pasechnik wrote: > > 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.
