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gap-system / gap

Main development repository for GAP - Groups, Algorithms, Programming, a System for Computational Discrete Algebra
https://www.gap-system.org
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RepresentativeAction fails on Symmetric and Alternating Groups #1431

Closed ChrisJefferson closed 7 years ago

ChrisJefferson commented 7 years ago

RepresentativeAction produces incorrect answers for both symmetric and alternating groups, with both OnTuples and OnSets, by producing elements outside the group. This bug was found by Mun See Chang

For example:

gap> RepresentativeAction(SymmetricGroup([5,7,11,15]),[7,11],[5,15],OnTuples);
(5,6,7)(11,15,14,13,12)
ChrisJefferson commented 7 years ago

Fixed in master in #1432, will need a seperate patch for 4.8.

stevelinton commented 7 years ago

PR #1453 should address this in stable-4.8.