Fix forced-orbit stabilization in AutomGrpSR - #6542
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When a someCharacteristics orbit pair lies in two orbits of the acting
automorphism group, the code appended the orbit of the first subgroup a
second time instead of the orbit of the second one. The position of the
second subgroup thus stayed `fail`, and the duplicated orbit list broke
the subsequent action homomorphism ("Action not well-defined").
The hook is reached via PatheticIsomorphism, which passes pairs of
matched characteristic subgroups as orbits; for non-isomorphic groups
such a pair need not lie in a single orbit. Found while investigating
issue #6537, but independent of it.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
fingolfin
added
kind: bug
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #6542 +/- ##
=======================================
Coverage 78.98% 78.98%
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Files 684 684
Lines 294205 294205
Branches 8647 8647
=======================================
+ Hits 232369 232370 +1
+ Misses 60028 60027 -1
Partials 1808 1808 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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hulpke
approved these changes
Aug 30, 2026
hulpke
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Yes, this is indeed what was needed here, unclear why the wrongly copied index never showed up in any test.
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When a
someCharacteristicsorbit pair lies in two orbits of the acting automorphism group, the code appended the orbit of the first subgroup a second time instead of the orbit of the second one. The position of the second subgroup thus stayedfail, and the duplicated orbit list broke the subsequent action homomorphism ("Action not well-defined").The hook is reached via
PatheticIsomorphism, which passes pairs of matched characteristic subgroups as orbits; for non-isomorphic groups such a pair need not lie in a single orbit. Found while investigating issue #6537, but independent of it.Co-authored-by: Claude Fable 5 noreply@anthropic.com