Opened 5 years ago

Last modified 5 years ago

## #22765 closed defect

# Fix cycle_index for permutation groups on non trivial domains — at Initial Version

Reported by: | Nicolas M. Thiéry | Owned by: | |
---|---|---|---|

Priority: | major | Milestone: | sage-8.0 |

Component: | group theory | Keywords: | gap, permutation group, Pólya enumeration |

Cc: | nborie, Dima Pasechnik | Merged in: | |

Authors: | Nicolas M. Thiéry | Reviewers: | |

Report Upstream: | N/A | Work issues: | |

Branch: | Commit: | ||

Dependencies: | Stopgaps: |

### Description

The code for `cycle_index`

predates permutation groups with arbitrary
domain, as well as their `cycle_type`

methods. Instead it goes through
plain Permutation's, which only works if the domain is 1,...n::

sage: G = PermutationGroup([['b','c','a']], domain=['a','b','c']) sage: G.cycle_index() ValueError Traceback (most recent call last) /opt/sage-git2/local/lib/python2.7/site-packages/sage/combinat/permutation.pyc in __init__(self, parent, l, check_input) 519 for i in lst: 520 try: --> 521 i = int(i) 522 except TypeError: 523 raise ValueError("the elements must be integer variables") ValueError: invalid literal for int() with base 10: 'a'

This ticket fixes that, and uses the occasion to clean a bit the code,
using in particular the `conjugacy_classes`

method to avoid a direct
access to GAP.

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