Glöckner–Neeb multiplication-growth question

At least 13 years old · documented by

Is the Glöckner--Neeb multiplication-growth condition automatic for every Mackey-complete continuous inverse algebra?

References

Progress summary

Refreshed
Claimed solved

A 2026 preprint claims a counterexample in an even stronger setting than the question assumes, but the result has not yet been independently confirmed.

The question asks whether the Glöckner--Neeb multiplication-growth condition is automatic for every Mackey-complete continuous inverse algebra. Glöckner and Neeb formulated the relevant regularity framework in 2012; their results gave sufficient conditions, not automaticity.

Known results

  • Glöckner--Neeb, 2012: A×A^{\times} is regular when AA is Mackey-complete and locally mm-convex.
  • The 2012 work does not establish that the multiplication-growth condition follows from Mackey completeness.

2026 counterexample

A 2026 arXiv preprint claims to construct a complete complex continuous inverse algebra whose unit group is not even C0C^{0}-semiregular and whose multiplication-growth condition fails. Since completeness is stronger than Mackey completeness, this would give a negative answer; the same work claims infinite-dimensional positively graded examples with failure of CkC^{k}-semiregularity for all k∈N0∪{∞}k\in\mathbb{N}_{0}\cup\{\infty\}.

Current status (as of July 2026): A complete counterexample is claimed in an arXiv preprint, so automaticity has a claimed negative answer; independent verification remains open.

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Solutions 0

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