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Periodic 2-cuts characterizing Z-splittings without hyperbolicity

Determine whether every compact, essential, non-positively curved cube complex X without 0- or 1-cuts whose fundamental group π1(X) splits over Z necessarily admits a periodic 2-cut.

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Background

Theorem 3.5 establishes that in the hyperbolic setting, π1(X) splits over Z if and only if X admits a periodic 2-cut, using the algebraic annulus theorem and Whitehead complexes.

Extending this characterization beyond hyperbolic cube complexes is open; one direction (periodic 2-cut implies a Z-splitting) follows from the algebraic annulus theorem, but necessity remains unproven.

References

This final section contains some open questions that are suggested by the results of this paper.

Question 6.7. Let X be a compact, essential, non-positively curved cube complex without 0- or 1-cuts. If π1(X) splits over Z, must X admit a periodic 2-cut?

Surface groups among cubulated hyperbolic and one-relator groups (2406.02121 - Wilton, 4 Jun 2024) in Section 6, Question 6.7