Defectlessness from adapted top-degree-p slices

Identify additional hypotheses under which defectlessness of all adapted top degree-$p$ extensions $L/K_{H_i}$ implies defectlessness of the full finite Galois extension $L/K$.

Background

For a ramification-adapted decomposition of an elementary abelian Galois group, the paper proves that all ramification ideals are principal exactly when every associated degree-pp extension L/KHiL/K_{H_i} is defectless. Kuhlmann’s degree-p2p^2 example shows that these top slices can all be defectless while the full extension has defect. The unresolved issue is to find supplementary assumptions that eliminate this phenomenon.

References

Thus a remaining problem suggested by Question \ref{Quesaboutramif} is to find additional hypotheses under which defectlessness of all adapted top slices does imply defectlessness of the full extension.

Ramification ideals for products of pure subgroups  (2608.21210 - Novacoski, 21 Aug 2026) in Section 5, “Final remarks and open problems”