#14543: Implement compositional inverses of cycle index series
------------------------------------------+------------------------------
Reporter: agd | Owner: sage-combinat
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-5.11
Component: combinatorics | Resolution:
Keywords: species, cycle indices | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: u/agd/cis_comp_inv | Dependencies:
Stopgaps: |
------------------------------------------+------------------------------
Comment (by darij):
I've uploaded a bunch of suggestions: [attachment:trac_14543-suggestions-
dg.patch]. Do you agree with them? I'm not sure of them myself, as some
of them are just my guesses. And I have not filled in the definition of
functorial composition since I don't fully understand it myself (I don't
have the [BLL] reference, only [BLL-Intro]), but I've added a #TODO
because it should eventually be filled in.
In the stretch doctest, I replaced {{{f = CIS([p([1])])}}} by {{{f =
CIS([p([]), p([1]), p([2]), p.zero()])}}} because, as far as I understand,
when you write a cycle index series as a power series in t, the
coefficient before {{{t^n}}} has to be a symmetric polynomial homogeneous
of degree n.
I have removed the reference to [BLL] from your method because the same
reference appears in another method. Generally, every reference needs to
exist only once in the source.
I added the {{{res._name = 'res'}}} line because the examples in the
{{{define}}} method in {{{series.py}}} do that. Maybe it is cargo cult. I
hope you can shed light on this.
--
Ticket URL: <http://trac.sagemath.org/ticket/14543#comment:14>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/groups/opt_out.
