Fixing a bug in the cyclic sieving phenomenon

[stumpc5]

This patch fixes a bug in the cyclic sieving phenomenon.

Without the patch applied, we have

sage: from sage.combinat.cyclic_sieving_phenomenon import CyclicSievingPolynomial
sage: S42 = [ Set(S) for S in subsets([1,2,3,4]) if len(S) == 2 ]; S42
sage: cyc_act = lambda S: Set( i.mod(4)+1 for i in S)
sage: CyclicSievingPolynomial( S42, cyc_act, order=8, get_order=True )
[q^6 + 2*q^4 + q^2 + 2, 4]

while with the patch applied, you get

sage: CyclicSievingPolynomial( S42, cyc_act, order=8, get_order=True )
[q^6 + 2*q^4 + q^2 + 2, 8]

CC: @fchapoton

Component: combinatorics

Keywords: cyclic sieving phenomenon

Author: Christian Stump

Reviewer: Frédéric Chapoton

Merged: sage-5.7.beta1

Issue created by migration from https://trac.sagemath.org/ticket/13997

[fchapoton]

Attachment: trac_13997-v2.patch.gz

[fchapoton]

comment:2

ok for me. Positive review

[fchapoton]

Reviewer: Frédéric Chapoton

[jdemeyer]

Merged: sage-5.7.beta1